Re: Surgical tubing...
It's used like sort of a giant rubber band, wrapped around the epoxied stock and the release-compound-coated action, to hold them firmly together. This eliminates the need for attaching the trigger mechanism and/or trigger guard and/or magazine plate, to the bottom of the stock, which would require that you stick those trigger guard screws up through the epoxied area and screw the action down normally.
NOT using the screws eliminates the possibility of getting some epoxy in the screws, thus making the job permanent!
For me, it eases my mind considerably when doing the setting of the bbl/action into the epoxy.
After setting the action into the epoxy "just right," you simply wrap the surgical tubing around the action with some tension (we're just holding the assembly together, here, we're not holding charging lions at bay), making sure to over-wrap the start of the tubing, and tucking the tail end of the tubing under one of the wraps. Voila! Everything stays just where you put it while the epoxy sets.
ETA--BTW, epoxy does not stick to surgical rubber, so if some oozes out, you can still get the rubber off with no hassle, then you have to cut and sand away the oozed material. I'd wait 'til it's set up to work on it, rather than trying to wipe it away as it oozes out.
As for the OP, he'd sent his trigger group away to be worked on--In the SKS, it's the trigger group that holds the action/bbl and the stock together, so he was forced to use some other means of attachment.
A final thought--Maskedman 504--if you don't like those voids in the bedding right at the butt end of the action, you can simply apply another coat of release compound to that area of the action, mix up a little more JB Weld and dab it into the voids, slap action and stock together once again, let sit for another 24, and bingo, no more voids. If they don't bother you (and with the SKS's anemic recoil, you certainly don't need extra strength in that area,) then just reassemble and be done with it--nobody else need know.
If you get too much bedding compound in there and it sets up, no probbie--just hog it out good with a Dremel tool or such, and re-apply. A nuisance to be sure, but a comfort in knowing that you're not stuck (pun intended) with a bad job should things turn out that way.