Hello,
Looks like a nice plan. In my opinion, UP is a great product (have it here and like to have it). However, to me, looks like it has a lot more 'oils and fillers' than M205. That said, I would choose one over another based on how well the UC finishes.
Generally speaking:
If I find that UC didn't let a very nice finish (using an orange pad), I will polish with M205 on white (polishing) pad.
If UC finish very well on orange, I would (majority of times) follow with UP on a black (finishing) pad. But also used M205 at this point, difficult to say one is better over another.
To resume my point of view, I do prefer M205 when I judge there'll be needed some 'polishing power' to improve compound finish, but I tend to choose UP when I find a 'glaze' will do the job.
Sometimes, I've just done 3 steps (UC/orange, M205/white, UP/black) before LSP. I tend to do this specially on black cars.
The 'third step' - UP/finishing pad - is really an easy task as you can cover a larger area, use less passes, less pressure and a bit faster arm speed. On darker paints, well worth the effort.
One thing to consider: UP oils and fillers are nice to be followed with a Meg's LSP (like ultimate past/liquid wax), as it has related 'compatibility'. I don't know if there will be any bonding issue with DGPS3.0, that way, I would prefer to UC/M205/LSP.
Another info about UP is that it also contains abrasives, so nothing keeps you from trying a test spot using it on a white (polishing) pad. That's almost the only true answer: test spots...
Hope I've helped anyway, please, ask if you have any doubt.
Kind Regards.