I'd stick with 7/8 OZ loads for a while. I'd also do as someone else mentioned and get the lyman hoading manual. You'll find so much valuable information in that book you'll wonder why you didn't have it all along. Back when my son was young and shooting trap with me, I started him out with 7/8 oz. loads and they hit the birds surprisingly well. I've also used them in my doubles gun for the first bird...Here's something that may help you out: