hehe good on you for teaching your DH! I think it is so cute when they become proficient with using mcn!
Sounds like you have a nice lot of nappies while bubby is small. I wouldn't worry too much about buying med's and lge's now as you don't know what size and shape bub will be. Plus they change shape too, like some nappies that fit at one stage may not fit a few months later (not just because they have put on weight but when their little legs and thighs change shape).