Yes, smalls and that is what Kris recommended. You will be amazed at the metabolism of these guys. Huge lump goes down over night and 2 days later its all but gone. I was skeptical about the size but a retic friend told me that was the right size as well. It sounds like your dude is a tab bit longer than mine. I think my boy is under 2 feet still. The lump of a small will be large but these aren't boas. They can take a larger meal like carpets, but digest much faster and because of that they need to eat more frequently.
That said, it is important not to overdo it. At this stage a meal that is big for them isn't going to have much influence on growth. I think I'll keep with smalls for a long while and then move up to medium sized rats and the quail equivalent. According to Kris and Cody, our males will eventually be maintenance fed large rats every 7-10 days or the quail equivalent.
I think staying within those parameters will set us up for lean and not overly large animals.
This is how thick Wallace is. I'm guessing you have a similar build on your guy.
NOW,,,,,, GET YOURSELF A CHEAP CAMERA and join the fun LOL!