Chuck away the PVA...use the epoxy with two coats, first coat put a good dollop and spread it by rotating the blank against the brush. Do this quickly over the whole rod section, then go back and lift off as much of the epoxy as you can with the brush, and scrape the brush against the pot of finish to get the excess epoxy off the brush. This should leave the thread showing the turns of thread. Leave to set, rotating as normal. After a few minutes, warm each whipping with a ciggy lighter -DO NOT ALLOW THE FLAME TO TOUCH THE THREAD- this will pop any remaining bubbles (the carbon Dioxide from the flame lowers the surface tension of the epoxy resin, and the bubbles will burst). After 24 hours, mix a fresh batch and use a new brush (I use builders fitches once and chuck) and apply a second layer, just enough to coat completely with a little extra over the foot of each ring.
The PVA is not as strong as epoxy, and if used forms a layer that the stronger epoxy cannot penetrate. It used to be used as a colour preservative, along with things like banana oil and cellulose lacquer, the advent of the NCP threads should have seen it off, personally I prefer the regular threads as they have a sparkle that the NCP types do not have. I haven't used fillers on rods for over 30 years, any comments Stan?