If you don't mind the speed loss, you can go with Dacron string and use 2219's with significant results.
I used to insert a 1/2 inch plug of rubberized quiver foam into my arrows as I assembled them to not only gain some FOC but also deaden the sound. This would only be possible if you build your own.
It adds about 5-7grns right behind the insert where you want it.
To cut these out you use a section of a 23,24 or 25 series shaft which you use a taper dremel grinding stone and hone it to be somewhat sharp.
Push it thru your foam sheet (1/2" to 2" works) and to remove simply push it thru with a 22 series shaft(like the ones you are assembling).
Then you simply insert it into the 22 shaft by compressing it enough to get it in, seat it down with your insert, but don't push the insert all the way, stop at the final seating ridge on the insert(those of you who build arrows know what I am referring to).
Then simply heat up your insert like normal, and use some of your hot melt like usual, only this time just for security I put a dab on the bottom of the insert so that it adheres to the foam plug. This is probably not needed as the compression of the foam will keep in place most likely, but I never like to lleave things to chance.
I like the 2512 shaft for a cutting tool because I used to shoot 23 series arrows, but I am sure the 24 or 25 series would also work on 22 series bolts/arrows.
The best rubber foam to use is "cold water pipe" insulation, it has a high rubber content.