Don't get me wrong and this is my personal opinion, but SSR2.5 and SSR1 combo is almost impossible to beat with the PC or UDM.
Here is a little write up that I did for SSR2.5:
-Always use a
polishing pad with SSR2.5 (it'll remove a ton of swirls, if not do another pass or bump up to another product)
-DO NOT PRIME WITH ANYTHING OTHER THAN THE PRODUCT ITSELF (very crucial)
-Apply a thin bead of product around the pad for each section of the car
-Spread it at whatever speed you want, work it in at Speed 6.... don't be afraid of speed 6.
-Work it in until very clear (may take a few minutes)
-If the product begins to build up on the pad, brush off with stiff brush or wipe off excess polish with a terry towel
-Wipe off
-Admire no swirls
-Go to finer polish (if needed- with the polishing pad you most likely don't NEED to follow up but it wouldn't hurt).
-Do not use a new pad that hasn't been washed- Pads come from the factory with small foam particles left in the pad that look like product dust.
I follow the above to a T and have had fantastic, swirl and dust free results.

. But if you are working outside or very hot conditions, that'll dry out the polish faster.
If you find something that works, stick with it

. If you do get the chance (or the urge) Menzerna's Professional line would be a good choice as would Pinnacle XMTs. But if you are satisfied with the results you are getting now, then that is all that matters.