Just as an experiment, why not put a long, heavy spring in there JUST to see if it continues to wet sump. ?? That would be a sure way to eliminate one or two variables. Why ASSUME that the stock spring is either long enough, or putting enough pressure on the ball?
I hear you on the shifting. I rode a knuck with a "suicide" shift, shift lever directly off the tranny, and a foot clutch, that did/does NOT stay in/engaged if you take your foot off it, for like 20 years. At one time I believe I could work that clutch and shifter as well as anyone with a hand clutch and foot shift. Then I rode a hand clutch for about ten years, then last year I put together a big twin flathead with the same clutch and hand shift set up. I thought it would be like getting back on the perverbial bicycle again. Wrong! Took 50 miles just to get somewhat reacquainted with it, to where I didn't feel like I was flying a helicopter for the first time, and 1,000 miles later I'm not quite back to where I was on the Knuck. !!! But I'm close...or at least now comfortable in city traffic. Takes a "little" practice!