I had infant size for my boys. They were a little snugger round the middle with Si, because he was a bit chubby (Riv was skinny). But they still were a good fit.

ETA: Poor you Gigi, missing your sewing - can you save up and just get a super cheapie kmart one or something next time they're on sale? They're getting cheaper all the time, and it would be better than nothing right? I can do basic sewing on mine, and really, it still might be better than the machines my grandmas had.