I assume OP started the trial in order to get benefits for his upcoming vacation.

My advice:
Can you get 5 single night stays in August? You could get the SW $317 credit plus your diamond bonus and the 5 X 1,000 bonus trial bonus. I would let it post as points then after the points are in the account call and change over to miles because a few of the agents don't understand that you get diamond bonus on mile stays also The good thing is you would have an emergency plane ticket for future use.

If you are one of the lucky few who live in a place swarming with Hyatts like Chicago and Dulles area it would be easier because you can hotel hop, but since you mention the $90 rate I assume your choices are limited like mine.

Look at prices around labor day weekend, because holidays are usually cheaper. As mentioned before most Fridays and Saturdays are usually the cheapest but I also check Thursday because sometimes it also goes down. Sunday (unless it is a holiday weekend) is usually more expensive near me.

If you can get the 5 stays in August, Maybe a few around labor day, and then wait as long as you can to see if a new offer opens up. Also if you don't make it then at least you got your recognition during your vacation and (assuming 5 stays) made platinum with some great bonus points.

good luck