I've been both practicing and doing dev work on an Asus tablet using the ArduinoDroid app. That let me work on code during my lunch break and practice my typing on the treadmill and elliptical. For no apparent reason the tablet stopped accepting OTG connections, so I can neither type nor upload. I tried different OTG cables and different devices with no use, and I could successfully attach the keyer to other tablets. So now I either have to hump my laptop or find a new tablet.
As far as progress before the tablet started acting weird, I can touch type pretty much the entire alphabet. For some reason F and J always give me trouble. Haven't done much work on the symbols yet. Most of my current practice involve typing pangrams or working on a short story I'm writing for my fiance.
Code wise I'm working on tuning the keyeing algorithem. Type on release is good for training but I think it slows down typing. There will be a "pro" mode where if the chord is held down for N milliseconds it types. Figuring out the exact tuning to maximize speed and minimize mis-keys is proving to be trickey.