I've seen this topic somewhere... Anyways, it took me 3 days to play at my mouse/kb level, and 1 month before I got comfortable with it.
Forgot the thread with tablet optimizations but... 1) osu! options-->Input-->"Enable OS TabletPC support" & make mouse sensitivity=1.0x 2) If you're using Windows, disable aero theme if it's on to reduce input lag 3) Download bamboo drivers, and mess around with the tablet area until you're comfortable (absolute tracking and forced proportions help)
took me 1 day of about an hour, then I slept on it, and the next day I was beating my scores after about 3 hours. It also helps if you can put your tablet in a consistent place each time you play. For me it is aligned with my monitor's base and the edge of my desk. Good luck!
it took me about 30 minutes to move from mouse only insanes to tablet+keyboard insanes
if it took anyone any longer than this, they are a baby
Was experimenting with mouse, and found that moving from mouse to tablet is kinda like changing DPI. I calculated my tablet's area to be about 233dpi, so I changed my mouse to match 2x of that as close as possible (about 670 dpi) and the transition back and forth is nearly effortless. (I could set my mouse to 1:1 DPI with tablet, but it would require more energy as a mouse is heavier than a pen. 2:1 DPI still allows me to reliably hit jumps)