I have pillar bedded quite a few Remington 700 plastic stocks. The problem is that the foreend is weak. I usually use aluminum arrow shafts to stiffen the foreend. I bring the arrow shafts all the way back to the recoil lug area. I use two. One is better than nothing. The only bedding material that sticks is Devcon (I use Devcon Steel) I under cut the stock to lock the bedding in and I really hog the stock out. I use several layers of red PVC tape in the barrel area that I want to free float The Devon goes from the forend to the rear tang of the action. I use plumber's putty to fill the voids that I do not want to fill with bedding. I use black shoe polish as a release agent. I would not worry about drilling through the the Devcon will take care of that. With a plastic stock the pillars are really not needed. They were used in wood stocks and hollow fibre glass stocks to keep the floor plate from crushing the stock when the screws were tightened. A plastic stock will not crush. I have done it both ways and now I don not pillar bed plastic stocks. I have not seen any improvement using pillars.
That is the way I do it.
Best regards,
Grit