I'm flying SFO-ORD on Monday and returning on Tuesday. My client meeting on Tuesday is late enough that my only option for the return was the 8.30PM CO metal flight. I booked it on united.com without considering the option of booking the itin through Continetal and want to maximize my UDU chances while not jeopardinzing the double miles from the ORD-California promotion (yes - both fares are W or higher), which requires round trip for the MP version. Two questions:

1) Do I need to do anything active to get on the Continetal upgrade list, or will it sort it out automatically? I think it is automatic but haven't done this before so am checking.
2) I think I am still better off for upgrades on the return being a Continental Platinum rather than a 1K. If so, is there a way I can switch in my Onepass number for upgrade priority and then switch back to MP before the flight to qualify for the double miles as a round trip?
3) Can I put the outbound leg as MP and the return on OP on the same itinerary, which wold maximise my chances of clearing both legs?

Apologies if this is a duplicate thread - but I couldn't find a thread that answered all of these questions and posting in in the DEQM thread yesterday didn't get an answer. Thanks in advance for any help.