So you pour the pillars first with the action in the stock with a set of screws coated to prevent epoxy bind..When cured bed again and put the action in and let it cure to achieve the posted results?
When I did mine I actually bedded the whole rifle at the same time. This was a really, really, really (emphasis added), really bad idea. It took me over an hour to defeat the various mechanical locks I had created. And I had to redo the DBM, magwell and rear tang.
My next time around I will do the pillars first. But you have to take into account where the epoxy will flow if you pour the pillars with the action in there. You'll want to have the bottom metal in there to have proper pillars on both ends. If the action is in there too all the surplus epoxy will flow through the action screw holes when you put the screws in, that would be bad.
So I would do the pillars like this:
1- Open the screw holes to 1/2" with counterbore, likely with a 5/16" pilot.
2- Tape over the pillar holes on the action side.
3- Pour the epoxy in the pillars from DBM side.
4- Thoroughly cover DBM in release agent and put in place.
5- Release agent on action screws and slowly insert down pillar all the way down to tape.
6- Depending on where you want the extra epoxy to flow you might want a hole in the tape. If not it will flow in the DBM.
7- Remove the tape and push the screws through. If you're using Devcon you won't have to worry about epoxy falling out of the hole.
8- Cover the action in release agent, especially inside the bolt channel in case epoxy gets in there, and screw the action in.
9- Use only enough torque on the action screws to sit the action properly.
10- Let cure for 24 hours, take apart, remove excess, and inlet the action, DBM, or whatever you want to bed next and repeat.
So I would do the pillars first. I would then do the action and DBM in the next step. I would then finish with the barrel channel.