I do, but in reality not me or anyone else can really tell you how to use the stick. After all it's your hands and your stick not ours :) Just find a way that's more comfortable for you.
I assume you were using the pad before. So did i, and from my experience Mitsu felt just sooo much better with the stick, especially his JFs.
As for "mastering the stick".. well i've been using it for 4-5 months now after about 2 years of playing on pad. I can't really say i'm close to mastering it or the actual game for that matter. But i love it. Can't really go back to pad.
Also only using 4 buttons is really great because now my right hand has 1 finger for each button except my pinky. Thumb for "G", index for "A", etc.
Makes the whole execution just that bit more precise. I was using bindings before and while that has it's advantages, 4 buttons is just a more natural way to play this game IMO.
As for holding the stick just do a search on youtube and you'll be able to find something to your liking. But i think it's much better to just take your time to fiddle around with it and find the most comfortable hand position yourself. Personally i use the "eagle grip" or what's it called when the stick is between my ringfinger and pinky with the palm facing upwards, but that's mostly cause i main Taki and that's an easier way for !me! to do all the PO shenanigans.