the only thing with flips though if he's a heavy wetter they might work so well. Having said that quite often there's only one way to find out for sure
You can get some quite girly nappies but equally some quite boyish ones too. Blueberry and Itti do some lovely ones.
I was just going to say this, I love my pockets and all-in-2s and they are amazing on DD, but would never have cut it on DS, I had to use really heavily boosted 2 parters on him as he just wee'd sooooo much, get mother and baby mag, theres an offer for a free nappy and wrap in there. If you like it little lambs are really good value, I'd recommend getting bamboo as it sounds like he wees quite alot!