I don't have anything real solid advice wise, but I wanted to add that I also think it's okay to try some WCM pre-1 year if you think it will work for your LO. It's not like the day they turn 1 they are suddenly ready for it you know? Some babies are probably ready to wean at, say, 10 months, while others aren't ready until 13 or 14. Do what you think is best!
Anyway, my only two thoughts are a) try mixing either formula or WCM will BM... start off with mostly BM and work your way up. Maybe this way you can get him used to it gradually. And b) I was told at LO 9 month appointment that she needs a minimum of 16oz of formula a day through a year. I just thought I'd throw that number out there in case you were looking for a goal amount or something. I've also read 20oz as a minimum on here.