With practice (and you will get lots of practice!!) you should be able to get the whole fairing off in under 15 minutes and back on again in around 25. Well that's my best time anyhow! You can get the battery out by just taking off the belly pan and one of the big side panel fixings at the back.
The dzus conversion i believe is non reversable and i'm not convinced that the looks of it would suit the ST bikes.