It is so refreshing to see posts from people that aren't living on the negative side of the half full glass.
Flats on the BB4 that is awesome vacuum levels. You could see if a little vac oil on the top of the piston would enhance the vac reading. A dripper on the inlet to let from a hit and miss style motor is the best way. A small 1-2 ounce dripper will insure she is not over oiled. The oil will seal any minor scores on the cylinder wall. If there is no increase then no reason to bother with a rebuild. 10 drips to start and then a drip or two a minute while running should do the trick.