if the advice on the side of the formula carton says

[ObsidianBlackbirdMcNight]

130mls 6x in 24 hours, and i'm giving him between 350-400 mls + boob, i'm providing roughly half his milk, yes?

he put on 10oz last week! i haven't increased the amount of formula since last week tho, i'm hoping as he grows my bm will pick up the slack. what do you think? he's getting weighed again on monday, i guess we'll see?

Sounds like abt half his milk. And yes your breastmilk should pick up the slack. If he's growing so well, could you gently cut down the formula and let your breastmilk supply increase faster. Kellymom has great tips.
www.kellymom.com/bf/supply/index.html