Some great advice here. Thanks all! We'll probably stay close to FRA and head to the FCT bright and early. When it gets closer I'll checkout the bidding thing. Also just received 11K SPG points so might do that although no CASh and Points option is available past December according to the SPG site.
CAPT Tee, we'd rather get the BKK TG F Spa experience than a free hotel at FRA.
If I had been thinking I should have tried to get the late night BKK-FRA TG flight to avoid any need for a hotel in FRA. Ah well, lesson learned.