Tacticool pillars

I'm wanting to pillar bed my tacticool soon, but I'm not quite sure how to "finish out" the front pillar. How does the bottom of the pillar relate to the outside of the stock?
For instance, with the rear pillar, the hole is drilled all of the way through, such that the trigger guard mates directly against the bottom of the pillar. (right...?)
How far through the stock does the front pillar go, and how is it covered from the outside, if that makes sense?
I'm a little OCD, and nowhere that I've read about clearly explains this.

If it is a dbm model, the mag surround acts as your bottom piece like the trigger guard does on the rear pillar. If it is a blind mag, there is a bushing washer (don't know what to call it) that the front screw passes through... if you pop that out of the stock, and then enlarge the existing hole (for the screw) but do not make the hole any larger than that bushing thing, it can serve as your bottom guide like the trigger guard when your reinstall it.

In other words, enlarge the hole with a slightly bigger drill bit, set the pillar on top of the bushing. Trim the pillar so it is proper height.

or you can just drill down from the top of the stock towards the bushing and stop when you hit the bushing. If it stays in the stock and does no get too chewed up by the drill tip, you'll be alright. I have done it both ways.