Yes 10w30 is better with heat than the ATF is. You can try going a little lighter in Weight, like a 0w30 but it probably wont make much difference. I run full synthetic 10w30
And the 2 shoe is better than the 3 shoe for a few reasons. Mostly that it is easier to get the 2 arms to grab at the same time than to get 3 arms. If the 3 arms are off by too much you can cause stress on the arms that grab first and they can break or at the very least cause very uneven wearing on the pads and then it wont function at all.
The jammer clutches uses a 3 shoe setup but the way those grab the clutch bell is different and they have a lot more surface to grab than the stock 3 shoes. The KTM clutches are only 2 shoe and are the most used in Euro moped racing.
Once you start getting into clutch tuning the shit starts getting real. Real annoying. Ha!