It is not a "left-hand twist", the 90* face does the cutting. Yes, the short flute has to be cleared often. Drills dead straight. I also drill half distance from each direction.
Half-stock ramrod holes are drilled using two under-rib and thimble guides, or fullstock in a perfectly aligned ramrod channel. Approximate ramrod location is confirmed with a small hole drilled under the barrel breech.
I've drill dozens of each with this drill.