As far as getting right into the crotch of the bead, I used little 3 inch pop-sickle sticks. Just wrapped the paper around one two or three times and as you can see in the last image, it gets right in there.
So after several hours and 1 single pass going horizontal on the shell, I ended up with this. I took a side road and polished it with just a flannel wheel and some blue compound to see how marvelous it would look, and instead ended up with all of these lines running horizontal. Hoping to avoid what I was told I would have to do. Ugh. Now for the next round, I took 600 grit and went the opposite direction. The short vertical strokes. Every increase in grit means going the opposite direction of the previous pass. This is where the jig became crucial. No moving or the next pass horizontal would be a bigger mess to clean up, instead of getting easier each pass.