If you get the fondant nice and thin, they only need a day or two to try (especially if add a hardening agent). I've never used MMF or the method on this site, for making bows... so good luck! They're pretty easy - just make sure you make a few extra, for breakage.
My first (and so far only) bow was out of MMF. It turned out pretty good, at least the gals at the shower thought so! It wasn't hard, but I agree about making the loops well ahead to allow to dry. If I had it to do over again, I would've made them much thinner, not just because it dries quicker, but because I think it looks prettier. I had seen a Wilton one premade in a box at Walmart (for $16 I might add), and matched the thickness of it.
The other tip I would add is make sure you tint your 'glue' to match the color of the bow or it will stick out like a sore thumb. I read that here somewhere and it saved me since I would've not thought about that until it was too late! 
Good luck,
Audrey 
Would they be little ones like these ? these are made of MMF..
I am baffled as to how you all get your MMF so workable!!! Mine is always soooo sticky!!! I knead knead knead the sugar in, and add in some Crisco, but it always seems to be too sticky to really be worth my while.
do you all dry them over broom handles? i am yet to try one and am pretty excited to do it
I have made only one bow, and it was gumpaste. I dried the loops on their side. It isn't the greatest bow...but I did learn that I am going to buy that Wilton roller that has the different edging.
Good luck.
Angie
I dry my bow loops all on their sides, I never heard of hanging them to dry - I'd be afraid they'd tear!
I dry mine on dowel rods and haven't had a problem. I usually dust it with powder sugar to make sure they don't stick.
I have only made one and it was difficult for me. I used gumpaste and I think the reason my was hard was because I didn't let it dry very long - I thought you just had to wait about 2 hours. Well, nevertheless, many of my loops broke and, well, it just looks plain messy. I can see all the blobs of royal icing in the middle. If you find a trick to getting this to work, let me know. Good luck!
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