For a good 303 sound, you could look at the Analog 303 Kit
And utilise performance macros. Macros give you quite a bit of that immediacy.
Not sure about that, but somehow 1/32 notes do really sound right in the A4/AK.
Slide behaviour is also tricky, because there are two types, constant rate and constant time.
Constant rate.
Constant rate means notes that are further apart will take longer to slide, with constant time, slide time is the same for all notes.
Most synths have constant time portamento, though.