No matter how you ride it, rings will seat in the first 20-40 miles max. The reason for pushing it harder in those miles is to really get them to seat, and not just smooth 'em down.

The boggin you have at low rpm could be just the opposite of what another posted, way too much fuel until the rpms pickup and more air is flowing. Careful riding it tht way, if too much fuel, you can wash down the cylinders, hurting the ring seating and you can never get it back. A lot of builders will set a map richer than required for a new build to keep from having detonation until it is tuned, but going the other way can actually be worse with long term effects.