Karl,
I have done quite few McMillans with pillars,and there isn't much more to pillar bedding that std.
I go the full receiver mortice,then add pillars route,other guys bed around the pillar job.
If you were to it the way I do:
Bed as normal,with floated lug,and sides of receiver.
Use a piloted Forstner bit to open up action screw holes to accept the pillars.
Reassemble the rifle,and do your math to determine pillar length.
Cut pillars.
Then I get silly with the moto tool inside the pillar cuts,and under cut them about 1/8" deep leaving about 1/8" on the top and bottom uncut so that the Devcon surrounds the pillar.
At that point I put the pillars on the action using sacrificial screws I have completely coated with Accra-release,mix epoxy,and fill the holes with it untill the undercuts are full and then a "Smidge" to allow for "Gush".
I keep the stock upright so that the epoxy dosn't flow back into the bedded mortice and push the action into the stock,untill it is seated.Then I tap the action with a rubber mallet to ensure it is fully seated in the bedding.I then mount the barrel in a padded vice,and then wrap the dickens out of the action with surgical tubing pulled TIGHT.
Then get out the Q-tips and clean up the excess that gushed out and around the floorplate mortice.Use the Vinegar to clean off any oopses that got on the stock before the epoxy kicks over.
When all is said and done 48 hours later,bed the floorplate mortice lightly as normal.
It works for me.Other folks have other methods that work just as well though.
Hope this helps.
Good luck to ya!!!!!!
S-28