I experimented along those lines years ago. Found how much 3F I needed to seat with a little even compression from the loading ram at almost full down. I like goo on top of the ball and that became the problem since the ball was so deep, hard to get a good even smear across the chamber mouth of a consistant amount.
Accuracy, at least in my hand, was good enough, as I recall, as good as the ball up top.
I like the way the COW or CM scours out the bore shot to shot so Ive gone back to that. I use a small flask now with small spout, easy to dispense (just like with powder).
FWIW, I run my caps through a number drill plate with a finishing nail to even up the skirts and the fit on the nipples. There is quite a variation out of the tin.