All formulas are the same nutriotionally. Some are 'lighter' than others and have slightly different make-ups that agree with some children more. All 3 of mine have been on SMA... a lot of people don't like it as it's heavier, but mine have all been fine, and BIG eaters! lol
Apetite depends on the child as does regularity. 6oz is a standard feed for my now 8mo and he has taken that since being 2m. However my now 4.5yo would take 8-9oz at a time at 4m! My 8mo wakes up 2-3 times a night still, but usually only takes 4oz at a time. I confess I do it completely 'wrong' according to the guidelines so I'd never recommend following my method. I sterilise my bottles, then make them up with hot water. I then place 1 in a jug of cold water to cool quickly, and the other 2-3 get cooled in the sink then put in the fridge. I leave the one in the jug on the side ready for when I need it at about 9pm (he goes to bed at 7ish). He generally only wakes every 2-3 hours but lately it's more as he's learning to crawl and is babbling.
When I go up to bed, I take 1 full bottle up with me and put it on the side at room temperature. He will wake for that one around 1am but will sometimes 'snack' from 11pm-1am. Once he's asleep after that feed I'll go and get another out of the fridge and put it on the side. He'll then sleep til 5am when I give him another feed when he takes a full 6oz and will sleep for another couple of hours.
I've done the room temp milk since birth to stop me having to worry about heating the milk up in the middle of the night. I have done it with all 3 of mine and it's what works for us. I have such big eaters that it never sits out for long! lol
I've always pre-made feeds too. Having to make them up each time is a such a hassle. Sometimes I'll make each individual feed up but I'll make it immediately they finish a bottle, so there's always at least 1 there ready. I keep them in the fridge and either sit them in hot water or zap them in the micro for 30 seconds to bring them back up to room temp. Always shake the milk and check the temp if you microwave it....it's easyt to over/under heat and either it'll be too hot or it'll still be freezing lol.