Tanya - are you an experienced sewer with new machines?
or a newbie with new machines?

i'm a newbie
if that is you too, i would suggest, you get an old flannelette sheet, cut up liners and practise overlocking on liners - i do double layer - great for nappy rash times, and now we use them for day time fitteds - but i digress, i found overlocking loads of liners has refined my crap overlocking skills heaps - i can even do acceptable curves now!

if you already know what you're doing, well - i got nothing - cos the possibilities are endless!!! but MCN fabric is not cheap, so i'd prioritise according to what your baby actually needs.