Hello OP,
I have traded through II for both Vistana and Marriott properties, and have different strategies for each. I don't know if this will be helpful, but this has been my general approach.
I own three dedicated trading properties, Marriott Shadow Ridge Enclaves (like an SDO, is two 1BR deposits), Marriott Willow Ridge (a 1BR/Studio) and Worldmark, which is a point-based timeshare system but has surprising trade power in II -- but alas no preference. SDOs could have an interesting role in the new trading world.
In Marriott, the owner makes a reservation at their home resort and then deposits it into II. This is a superior approach (for the owner) than Vistana's approach of giving a blended deposit to the Vistana week owner. If I can reserve a Marriott week that is a desirable deposit (Feb/March Palm Springs, July 4th in Branson) then I will deposit that week into II and I believe I have a better deposit with higher trade power than a blended week. In Marriott world, we think alot about how to maximize the trade power of our deposited week.
I then consider what my target exchange is -- if it is a rarely available week (like a 1BR in Summer at Maui Ocean Club), then I will sometimes deposit an intact 2BR Willow, because in the exchange world, there is real trade power differential in offering a 2BR for a 1BR, and you move to the top of trade stack. In TUG, we usually seek an uptrade and try to get a 1BR for our Studio or a 2BR for our 1BR, but sometimes I prefer to have an advantage in getting a rare week. And if I NEED to get the trade (ie, the specific week is important) than I will often downtrade an intact 2BR for a 1BR (or 1BR for a Studio) to increase my chances.
If you want to play with the Marriott trade world, before buying a Marriott, I would consider (and assuming you own a 2BR Sheraton, I would deposit the fully intact unit and put in an ambitious trade (1BR in July MOC, Q1 for a 1BR in Aruba) -- that will be a fascinating trade test. Because there aren't many WKORV July deposits made by Vistana, this is probably your best chance to go to Maui in July and your only chance for Q1 in Aruba. Those are rare deposits in II.
Conversely, if you are traveling in September, you can feel better trying to trade a locked-off 1BR for a 1BR at either of MOC/WKORV (or uptrade to a 2BR in MFC or Aruba). This is something I really like about the new integration -- I can play across both systems because I like all of the properties. In Kauai, I like all of WPORV/Waiohai/Kauai Lagoons/KBC, and something has to hit there in a Like-for-Like trade???
The last thing I do that I think is a reasonable trick is making a reservation with points/StarOptions, and then trying to replace it with an II trade. If you make your desired reservation with StarOptions and then you place a matching exchange request for the same week in II -- if it matches, you get your StarOptions back. I did this recently with Waiohai, and my reward is getting my valuable points back, my risk is that I will get a bad room assignment and look at the parking lot instead of the beautiful grounds -- but it is a calculated risk.
I hope that helps -- apologies for the lengthy response!
Best,
Greg