If they are both neutered and bonded a few weeks later when the hormones have eased off, it shouldn't make much difference what pairings you do. I prefer 2 boys together as an easy bond, followed by boy / girl. I find that girls are feistier. Others have different experiences / opinions. Often it comes down to the individual rabbits and whether they get on together. They nearly always prefer a friend or two, rather than being an only rabbit, though. Always neuter both whenever possible, otherwise there will always be issues between them - as well as health risks to un-neutered girls.