Keep in mind that if flywheel shafts are running true there is no significant load on pinion shaft bush in cover. When I'd trued my flywheels (they came within half a thou), and installed in cases I used engineer's blue on the end. With cover fitted and flywheels turned, removing cover showed only the slightest hint of blue on the bore of the bush (which was the new modified repro bush, line reamed 5/8"). This shows that the pinion shaft runs central in the bush when everything is right, rather than running
on it. It 'floats' anyway, so lots of oil isn't vital. Maybe some load on bearing if engine rev'd really high and flywheels flex.
I would say that continuous oil to crank pin plus with that lashing around, plus the oil jets in the cylinders, together ensure that the cylinders/pistons are well oiled as standard. Having said that, I have put a 3/32" metering plug in the end of the pinion shaft. This is more in mind of getting the oil pressure light out at riding speeds below 40mph! I've also given close attention to the oil pump to ensure it's as it should be. A lit oil light is never reassuring.
In '59 Sporty manual, oil pressure at 20mph in top gear is supposed to be 6lbs+ . I can dream!
Some say that too much oil to the crank bearing can make rollers skate. All I can say is that on my used motor the rod fit was fine and everything looked very healthy when stripped, so reassembled with same parts.