I do my jeweling/burnishing via Cyclo, but I'll probably try it with the Flex some time. I don't do it via PC very often, and on *some* paints you'll have to be careful to pick the right pad/product combo or the PC might not give the greatest results (or so I hear).
My $0.02- Use a pad with zero cut, let the product do all the work. Choose a product that's *almost* functionally nonabrasive, something far too mild to do real correction (do all the correction before you start this process, don't leave obvious flaws with the idea that you'll "finish removing them" during the burnishing).
Note that other people approach this differently and combine their final correction (e.g., light hologram removal) with the jeweling.
I would *not* apply much pressure to the machine, again, the idea is to let the product do the *very minimal* polishing that's involved.
How fast you move the machine, and what speed/etc. you use will, IME, depend on the combined variables; seems like every machine/pad/product/situation combo calls for a certain machine speed (not an issue with the Cyclo

but with the PC I'd stick with 5 or 6) and a proper hand/motion speed (don't overwork the product, don't move so fast that it doesn't break down uniformly, don't try to cover too large an area at once).
I use very little product and basically work it until it nearly disappears, but *that's with the products I use and on my paint*. Some products, even very mild ones, need to be buffed off damp/wet or they'll cause micromarring...depends on the product and how hard/soft your paint is.
Example of what I do follows. Note that other products might be used in a *very* different manner.
On the Audis (hard clear), I first get them as close to perfect as I'm willing (nothing left but residual marring from RIDS that are IMO too deep to remove completely). Then I use the Cyclo with blue Sonus finishing pads and 1Z High Gloss (I suggest you use something milder on softer paints).
I rub enough 1Z HG into the pads to uniformly lubricate/prime them and from then on I use a tiny bit of polish for each area, just enough to keep the pads from drying out (I guess "almost pea-size" is pretty close, and remember that the Cyclo has two pads). As I add new polish, I try to distribute it evenly across the pads; I don't just put one big drop in the middle.
I go over a fairly small area (enough for the amount of polish on the pads) until the 1Z HG is pretty much "worked away to nothing" on the panel. At that point the *pads* still have some moisture in them; I *DO NOT* work things until the pads dry out! And I clean the pads frequently with a cotton towel and Meg's #34 so they don't get caked with old polish. I keep the pads very clean.
With the polish pretty much worked away to nothing, the minimal polish residue is easily wiped away with a plush MF, though I usually fog the surface with my breath before wiping. There isn't much inspection to be done other than making sure all the product residue is gone; the improvement is so subtle that it isn't obvious that I've done anything.