That's assuming the first set doesn't come out correctly.... First set I made were the best of the first 10! Scary!
Besides, assuming you will fail helps to make it happen.... read up on the techniques, practice the seperate skills, then make the tongs.....
My only advice would be to warm up with the practice skills, drawing, tapering, slitting, drifting, etc the same day you want to make the tongs... I've found that I make fewer mistakes and mis-strikes that way....
I also plan out each step so to minimize the time spent with the steel out of the fire.... Walk through the steps, especially for forge welding, before the metal is at the correct temp.... works for me.... ;)