Sorry if these questions have already been answered; I searched and read everything I could find on status matches and challenges and wanted some advice on the best approach given my situation.

I am Hilton HHonors Diamond (> 110 nights last year, almost 40 so far this year). I expect to spend about 30 nights in hotels by the end of June for business travel. Many of these nights will be at Hilton properties to requalify for Diamond VIP and take advantage of their Q2 promotion, but I should be able to do at least 10 nights at Marriott during this period too. At this point, I am uncertain if my business travel will continue past June 30.

So, my first decision is whether I should ask for a Gold or Platinum challenge. I'm thinking Gold, since I won't be able to meet the 18 nights if my business travel does not continue in July, and it appears that Marriott is pretty stringent about 1) one challenge per year, and 2) the policy of meet the challenge or go back to your current level (basic for me). Also, since Marriott Platinum is tougher to achieve than Hilton Diamond, I'm not even sure that Marriott would consider me worthy of Platinum.

A related question is whether anyone has been given an either/or type challenge (i.e., 18 days for platinum or 12 days for gold), or if Marriott actually does grant status for a lower level than the one you challenge for based on the number of nights stayed during the challenge period (e.g., if I am doing a Platinum challenge and only manage 13 stays, will I get Gold?). I'm assuming that neither of these things happen, but figured it could not hurt to ask.

Finally, I was wondering if Marriott ever considered stays before the challenge was requested/approved. I'm assuming they don't, but again I was hoping that someone has had a different experience.

P.S. I realize that waiting until I get clarifiication on the my travel beyond June 30 makes sense, but I'm not sure how soon that is going to happen, and I am planning Marriott stays beginning this week and don't want to lose the chance to count those stays to meet a challenge.

Thanks in advance for any advice!