Well, now I had better come up with something worth reading.
I seems like you are one the right track. You got the pattern down, and you have good materials and a nice blade. (and a very unique design at that)
Rawhide (also known as "bleached") stingray is tough to work with. The only time you really need to bother is if the strength of the hide is a issue. Such as with a traditonal tsuka. The tsuka gets most of its strength from the silk and rayskin. In this knife that is not the case. You would have been much better off using tanned stingray for this effort. Tanned ray is really flexable and easy to cut with a razor knife. It is also cheaper if you have a good supplier.
Since you have the rawhide that is what we will work with for the moment. Since you got it from Fred it is of a good quality and should be fairly flat. But most likely it is not flat enough to be easy to work. So, fill up a large sink with hot water. Soak the skin in the water for about 30min. Once it is good and soaked you need to get it perfectly flat. Lay a bath towel out on the floor and lay the hide out on it. Put another towel on top and put some type of flat board on top of the second towel and add some weight. About once an hour swap out both towels for fresh dry ones. Continue doing this until the hide is dry and hard again.
Now that you have a nice flat hide to work with you can apply that pattern you have made. It is totally up to you as far as what part of the hide to use. If you want only the best cut then you will only get one hide per knife. That gets mighty pricey after awhile.
Once you have the pattern laid out it is time to cut the hide. You want to cut it dry. Making it wet does not make it easier to cut. It only makes it more difficult to handle. How you cut it depend on what tools you have in the shop. I think that a bandsaw is best, but other power cutting tools work also. A scroll saw comes to mind. Do not use something like a jigsaw as this wil most likely chip the hide and blow out large sections. A very heavy pair of metal shears will work but it is hard going. If you are very limited on your tooling, a razor knife will work. Just be sure to have a good supply of blades on hand. The rayskin will dull a razor knife in a heart beat.
Now, you have a piece cut out matching your pattern. Fill that sink back up with hot water and soak your cut out hide. While the hide is soaking you will need to find some type of binding material. This can be rubberbands, twine or even masking tape. You just need something to wrap tightly around the handle and the hide.
Once the hide is soaked and is highly flexable it is time to apply it to the handle. Wrap it around the handle material. You will want the seam to be on the underside of the handle. Once the handle is wrapped you need to take a good look at your seam. If you cut the hide to big and it overlaps leave it for now. It is easy to came back and fix once the hide has dryed. If you have a gap, you need to make a choice. If it is slight (1/32-1/16) you may decide to leave it be. However if it is any larger you may want to cut a new piece. If the gap is to large it will print on the ito. You could also feel it in the hand.
If you are happy with the fit you need to bind it for drying. Hold the hide in place with one hand and VERY tighly wrap the binding over it. Once it is secured tightly in place set it aside for drying. Don't try to rush it by using a dryer or by putting it out in the hot sun. Just set it aside in the shade and give it the time it needs.
Once it has dried, and you have removed the binding, the hide should be able to be removed from the handle. If you had an overlap now is the time to fix it. A bandsaw is really the best tool for the job but I guess that a hacksaw would work if you are careful. Simply cut the offending overlap off so the both edges just barely touch.
Once you are happy with fit, slide the hide back in place on the handle. You are now ready for wrapping.
As to you question on applying epoxy.
I do not use epoxy. It is sticky, messy and smells awful. I prefer CA (ie. Superglue). Once the handle is wrapped and you are fully happy with the job (note: once you start applying sealer, you are stuck with the job) apply the CA in small amounts until all the silk is totally wet. Set the knife aside (making sure not to touch the handle) and give it a few hours to fully dry. If you touch wet CA, not only will you stick to your knife, you will get a white frosty fog all over your ito. It is better to be safe and wait. If you do get a little frosting, a second coat of CA will normally get rid of it. The more coats of CA you apply the glossier the ito will become.
If you decide that epoxy is for you, then flux brushes are the best bet. DO NOT buy them from Home Depot or any similar company. You will get raped on pricing. You can get them online from both WoodCraft and Rocklers. They sell them for applying wood glue. I think I normally pay about $7 for 100 or something there abouts. You do not "need" to coat the rayskin. But it is your choice as to whether or not you do.
Thats about all I can think of at the moment. If you have any other questions please feel free to drop me another line.
Ever notice how sometimes you want to rush to the next step cause it sounds like more fun? And almost everything's more fun than rubbing out a blade...