Work slowly, using light pressure and lots of water to keep the paper from loading-up. Be careful around and raised areas, the sanding force gets concentrated over them. Work the large, flat, areas first - then go back to take care of detailing the small, localized, spots - one at a time. Shouldn't take much more than an afternoon's worth of massaging to do those four pieces. If it takes twice as long, that'd still be less time than doing it all over again. And, this only has to be done once. What's 4 hours more or less, once the bike is back on the road and looking good for years to come?
2000 grit is fine enough that it should leave a dull shine. That's part of the reason I recommend using machine compound (with a diminishing abrasive) by hand. It'll take some serious elbow grease, probably 2-3 passes. IMHO, working slowly & gently will keep you from wearing through paint an damaging your work, a small price to pay for the safety factor and a first rate result.
FYI, it is possible to get show-quality results from rattlecans. Catalyzed urethane is catalyzed urethane. While there are some quality differences among products, chip, chemical and UV resistance are comparable among them. The main drawback to rattlecan paint is the lack of application control, including flow rate, possible with a spray gun. With small parts such as these, it's not a bad fit and sweat equity can tame, or eliminate, most of the orange peel.
Methinks you're well on your way to a satisfying result and this time around will be the charm.