On mine I've got o rings under some of the heads of bolts on the bottom as they leaked otherwise, and at least one on the bottom has gasket goo on the threads as it leaks through them - this being where the bolt hole goes all the way through the inner case, not all bolts do. I fitted a longer bolt and put a nut and fibre washer on one, behind the case, which also helped.
I make my own gasket and it protrudes by a few mm inside and outside the case, this seems to help by making it stronger. I trim extra off the extra gasket where it shows. It's 1.5 mm thick paper "flexoid" brand from UK. I use loctite flexible gasket sealant, red colour.
There will most likely be a weep from the seal around the main shaft, as I don't think that seal design will ever not leak at all! though the sliding plate hole on mine is pretty worn and a loose fit on the scroll and it still doesn't seem to leak much.
I don't use ATF in the case as it made it leak more, I use sae 30.
Mine still leaks slightly from the gasket area a bit, not straight away, but after maybe a thousand miles or so
It's been like that for over 5000 miles now, and as I've no reason to have a look at the 6 spring clutch it will stay as it is until the next tear down.