OK, I've figured out that concept of FT is not working properly with my trades -- once I've put some FTs people got upset because they weren't able to bid (been at work, sleeping, etc) and many asks to "let me know before selling this", etc, etc. So I'm planning to do another thing.
I'll post "semiFT" prices in 24 hours (so it'll be around Friday, 18, 13:00/01:00PM UTC). Once I'll got bid equal to "semiFT" price, timer will start -- other people will have 16 hours to outbid this price with a step == Min(500, price*0.05). Each outbid resets the auction timer to 8 hours. Sounds complex? Sure it is!

But hope you've got the idea.
Again, if you've been previous customer I'm OK with you reserving items without having Fgs right now. It'll work with some limits of course.