I have a large (~12" diameter) buffing wheel I used on guitars, and it works great on drums too!
I have never worked with Vistalites before, but with appropriate compounds (3M makes a slew of good ones, but get the pro stuff not the consumer stuff) I'm sure I could make a nasty vistalite gleam again.
When sanding (and buffing) it is normal to give up early and go for the finer grade. With a freshly applied finish, we were starting with 600 (sometimes courser, depending on imperfections), then 1000 and then int the compounds. There are several we used but the main ones were 3M heavy cut (not used often), Medium cut and fine cut. There was/is also a swirl mark remover that sometimes was used, but the finer compounds we purchased as solid bars you would load the wheel with rather than load the item. A final treat might be Meguir's clear plastic cleaner, polish and finally detailer (usually just needed on gloss black). These last items will work well on your transparent finish too if you haven't tried them.
It sounds as if you have a good system going, but you need to spend more time with each compound before switching to the next.
Oh, most critical: Always use new, clean cloths/applicators as you proceed finer through the compounds, and a wash with a bit of dish soap in water between grades is highly recommended. This avoids rubbing in courser grit from heavier stages as you proceed through finer stages...
PS paper finer than ~600 (maybe 400) will not level the surface very well, but rather will follow it (more important when blocking out a paint or clear). Also, a drop of dish soap in your wet sanding water is a good idea and helps keep the paper from loading. Change the water often too!
