Always glad to help Especially since I love your stuff!

Yeah I use a basic round brush in photoshop, this allows me to quickly change the overall hardness of the brush with ctrl+[ and ctrl+]. Generally I like to block at full or near full hardness, a little softer for finer rendering and much softer for blending.

Figured I might as well upload the brush and save you some trouble
BRUSH: roundreactive.zip

I have a few settings on, I find this is the most efficient and most natural feel for me - allows me to vary how much paint I put down not only with pressure but with speed. The settings I usually use are as such; size to pressure, minimum size to 70% (lower and I find it harder to control when blending), opacity and flow to pen pressure, manual opacity always at 100% and flow I have lately had at 40%. Think of flow as controlling how much paint comes out in relation to time, very handy for finer control.

I'm not sure what you meant by thin, I think maybe you might set your tablet up to a "softer" feel so you don't have to press hard to get full opacity - it's better for your arms too, we have to worry about carpal tunnel and other RSI enough

I'm not surprised you jump between Painter and PS, I did too. I find it really difficult to get the edges I want in Painter, really you need at least two brushes - one soft and one hard to get what you want. You really can't beat PS's color editing either.

Let me know if this helps and if I can try to help you out with anything else
(It's 7am and I haven't slept so it might not make any sense...)