I do most of my handles at work on fridays(my day off,but some of the work during working hrs.too...shhh.)
We have 3) 4x36 belt sanders with 36 & 80 grit belts only.I do the rough shaping on the BSs then clamp the blade in a vise between 2 pieces of wood with the blade covered in masking tape & use the shoeshine method of sanding for finer shaping,then hand sanding.I sand the spine & as much of the underside as I can on a hard surface.(steel bench top or a board)For the radiuses on the underside( finger groves) I use the edge of a 2x4 & a sanding drum in a drill press.If I don't have the right size drum I'll tape a strip of sp around a piece of round stock,usually 3/8", give or take a quarter inch as needed.
I've used John's method of chucking the pins in a drill & pinching them with the sandpaper as they turn in the drill,works great & easy to control how much you take off for a good lose,but not sloppy fit.
And slightly taper the ends of the pins too.
I also will file groves around the center of the pins(solid pins) & just rough up the tubes real good.
Drilling very shallow holes in the mating surfaces of the scales is a good idea too.If there are extra holes in the tang & corresponding divots in the scales then the dried epoxy acts as hidden pins for more strength.
DON'T FORGET TO SHAPE THE FRONT OF THE SCALES BEFORE GLUING THEM ONTO THE KNIFE OR YOU RUN THE VERY PROBABLE RISK OF GETTING SANDING/SAW MARKS IN THE RICASSO WHICH ARE A PAIN TO HAND SAND OUT!!Ask me how I know. LOL
All sanding on the tang & the mating surfaces of the scales need to be done on a hard,flat surface to prevent gaps showing up between the scales & tang.
You need as strong a clamp as possible,preferably c clamps when clamping the scales to the tang after applying the epoxy.2 clamps preferably.
Of course you have to allow for the protruding pins so one clamp might be all you can get on,but try for one on each end.
Don't forget to totally cover all mating surfaces & the pins with epoxy.
I've learned what I have from the makers forums here,shop talk & youtube vids.
Hope that helps & good luck to everyone that decides to tackle a LRK+ handling.
Proud supporter of JK Knives # 67,and all makers of hand crafted goodness.
May the forest be with you.