I believe Acer is referring to a gap between the frizzen cover and the barrel. If your lug is only on the bolster there will be a gap at the frizzen cover barrel junction. An early contemporary maker, Bob Wolfe, always used a leather washer between the vent area and barrel to adjust for a wider area in the wrist. That also has some problems but works.
I do not find a problem with breaking through the ramrod channel. Structurally that thin covering of wood at the bottom of the lock inlet over the ramrod channel is not important. I always taper my ramrods so there is some extra room in that part of the channel, actually I often need the smaller ramrod diameter to clear the front lock bolt :-)
The primary concerns in the lock area should be function: 1) a good tight seal of the bolster and frizzen to the barrel 2) a solid pillar of wood from the bottom of the tang at the breech to the trigger plate that furnishes a place for the trigger guard lug 3) sufficient clearance for the sear and bottom of the mainspring so you do not eventually eat out a hole at the bottom of the lock inlet.
Tapering the bolster is an adjustment for not having a tapered barrel to accommodate an earlier wrist profile. We used to do that a lot when swamped barrels were hard to find. Today i would suggest starting with a swamped barrel if you want the early wrist profile and going with a straighter later wrist profile if using a straight barrel. The swamped barrel does not help with breaking through the ramrod channel however, that is a function of barrel diameter and lock spring design.
