First, go to Home Depot and get a long shank 1/8" bit. It will be a black oxide wood drill bit. You can cut the shank down to eliminate excess length if you want. It is helpful to have a pair of digital calipers as well.
To answer your question, yes. You can do the epoxy at the end. But you will have to make sure your handle is straight as you are trying to fit everything up, get the handle pin in and clean up all the excess epoxy squeezing out as you assemble everything. By bedding the tang early, you can remove and reassemble the handle as many times as you need with great consistency. You can do most of your handle shaping before glue up this way and know that when the time comes to epoxy everything that it will all go together as expected.
Here is an excerpt from a post I made a while back in another thread about fitting hidden tangs:
Place your block of handle material with what will be the side of the handle facing up. Lay your blade on top, positioned how it will be when the knife is done. Keep in mind any guard or spacer material that will be between the handle and the ricasso and space accordingly. Now trace the tang profile onto the handle block. You can use pencil, masking tape or whatever. Make sure you have enough room around the tang profile to execute the handle dimensions you have designed for the knife. It doesn't hurt to transfer your handle shape to the block as well. But for now we are mainly concerned with the tang. Indicate where the guard or spacers meet the handle block and draw that angle with a straight line. Make sure that the face of the handle block that will meet the guard or spacers is sanded FLAT, not necessarily perpendicular to the top and bottom edges, just that the surface is flat.
Now, turn the block up with the guard side up. Use your calipers (set to decimal inches) to measure the width of the block, divide by two and scribe a centerline. I don't know the dimensions of your block but we'll use 2" square for our examples. Next, set your calipers to the width of your block and subtract .120" and divide by two. Using our 2" square as our example, we get .94". Set your calipers to that number and scribe a parallel line to the centerline from each side, left and right, to establish the width of the tang. Use a small machinist's square or similar to transfer the front of your tang drawing across the face of your handle block. So you have the top and bottom of the tang established as well. You should now have the entire cross section of your tang drawn out on the face of the handle block. If you will be using an 1/8" twist drill to drill the holes, make a small mark 1/16" in from the top and bottom of the scribed tang slot. This will be the center of the drill dimension. Center punch these markings on the centerline. Add additional punch marks if you will be drilling more holes. Do NOT put additional holes too close together because the drill will wander into an adjacent hole and at the very least frustrate you, it might also break a bit that thin in the hole. Now you're really having fun.
Ok, now that the hole locations are punched you are ready to go to the drill press. I would suggest getting the shortest 1/8" drill bit you have and chucking it up as far into the chuck as it will go. I know it's not good to clamp down on the flutes but have an 1/8" bit set aside for this task. If you use one of those extra long bits it will flex while drilling and your holes will wander all over the map resulting in crooked handles. Especially if you have a wood block with hard and soft grain structures, the bit will want to avoid the hard grain and scoot over to the soft grain (path of least resistance, etc.). You want as stiff a bit as you can get to make the pilot holes. That's why you want as much bit tucked up into the chuck (within reason) as you can, to stiffen the bit. Lightly clamp your handle block in the machinist's vise. Chuck up a longer drill bit or straight piece of rod for this part. Start with one of the holes at either end of the tang slot. Position the vise with the handle block behind the bit so you can see the tang profile you marked on the side of the block. Loosen the block in the vise so it barely holds the piece. Adjust the angle of the block so that the drill or rod is parallel to one of the tang lines. Tighten the vise. Insert your short bit, align with punch mark on top for that side of the tang and drill the pilot hole. Adjust angle for the other edge and drill pilot hole. Drill additional center holes at appropriate angles for their position. Once the pilot holes are drilled, go back and deepen the holes with your longer bits. They should follow the pilot holes without problems. Use a long rod to test the depth of the holes to make sure you are deep enough and that you haven't overshot your depth, and to confirm that your holes are straight.
Next you need to hog out the hole. Start by using a sharp chisel to outline and clean up the face of the hole. Hogging out a hole that narrow will be a pain because you are limited in the kinds of tools you can get to fit in the hole. Make yourself a custom broach for these narrow slots. Sawzall blades and drywall saws can work well. Small chainsaw files might barely fit but I doubt it. In any case, you have to get all that webbing out. Keep digging and test fitting the tang until it fits. Keep checking that the blade is straight to the handle block as you go. It helps to work with a block with generous dimensions so you can compensate for slightly crooked blocks.
Once the tang is seated to the proper depth you will fit up your spacers and guard to the ricasso. Drop the assembly into your handle block and tune the fit to the handle block by adjusting the angle of the block face until all light gaps are closed up. Make every effort to keep mating surfaces FLAT.
When the fit is perfect and without gaps, take the blade/handle assembly and lay the knife on its side with the ricasso propped up on a flat and level block like a 1-2-3 block or piece of micarta etc. with the blade and handle suspended in air. You want to have the ricasso and blade edge level and parallel to your table top/surface plate. Using a pencil on top of a block of wood that puts the pencil lead even with the cutting edge, establish a line around the handle block. This line should be in line with the cutting edge, not necessarily in line with the center of the handle block. Now when you start shaping your handle you will have a centerline from which to work. As you work, shaping the handle, use a contour gauge to compare one side of the handle to the other.
