This depends on the surface. I would first try the PC and the white polishing pad. If this does not give you the desired results then try the rotary and again a polishing pad.
As noted keep the rpm's around 1200 to 1400. I have never really had to go any higher than 1800 rpm's and this was for paint in pretty bad condition.
Also as correctly noted, if the white pad does not give you the results you seek (when used with a rotary) then bump up to an orange or wool pad. Optimum can take your paint from the leveling stage to the finishing stage with the proper use of polishing and finishing pads.
The work time of Optimum is just about infinite. I was hard pressed to dry the product out when I demo'd it several days ago, and this was with a rotary. The negative comments I am hearing from others about the Optimum is that, to them, it is too oily. This is a GOOD type of "oily" though as this is what acts as a "barrier" (buffing barrier as Kevin puts it) between the pad and the paint. This helps in achieving reduced heat and a better flow of the buffer. They are not filler oils.
A detailer here in town got some from me and said he has a hard time with it because, "It doesn't work like my other polishes!" I told him to work it twice as long as he would, say, DACP or any 3M product, which he did and now he can see the benefit and results of the product.
Products like IP or DACP may cut faster than Optimum Polish but I believe the Opt. will give better results with a longer working time and less time spent in clean up.
Hope you like the product and if I can be of any further help please let me know.
Anthony