Please start a new thread for your issue, it gets too confusing when more than one issue is being discussed in the same thread.

 

sounds as if the breather system is not working. the hd engine need diff'l pressure to move oil around and in low to upper mid range rpm, the c/c will have a slight vacuum. if you run upper rpm, oil can pool because the pressure is equalized through out the engine.
on some bt where the tank is below the engine sump, and the vent from the tank is covered with oil due to over filling, it is possible at steady throttle to develop vapor lock which will cause the oil to pool but varying the throttle usually make it quit.
run a leak down test to see how the top end is holding up, anything below 90% is suspect.

 

Coming back to the wet sump problem, like you I found that a new check ball was no help. I did two things which reduced, but did not eliminate the problem. I set a new ball in the pump and gave it a good rap with a small drift. The other thing I did was weld a new ball to the end of a weld rod. I applied a very small amount of grinding paste (I know) to the ball and used the rod to rotate the ball back and forth, thereby cleaning up the seat in the oil pump. This involved very carefully wiping out the seat to get rid of residual paste. I sold the bike to one of my sons and it's got about !02k miles on it, still running strong so I got away with it. He finally eliminated the wet sumping with a new oil pump, S&S I believe.

 

one big issue with the ole stuff is there is no seal in the scavenge side. there is a seal between the feed and scavenge sections. usually seat grinding and ball rapping produces no results. why???
well the oil is not by-passing there, it is leaking past the pump shaft. there are several ways to mod the pump and i have several for the xl.
as far as the ball goes, a teflon ball works best and will conform to the seat.
also as hd progressed, they often updated things which was mostly to save them money. one very good example was to get rid of the captured ball with tangent seat to a floating ball with a conical seat, this save a lot of machine work.