Question about a juvenile retic's feeding schedule

[KyleKennedy]

I have a year old mainland male. I had for him about 3 months now, and have been feeding him a small f/t rat every Saturday. Yesterday, I offered him a f/t jumbo rat and he ate it with no problem. Took him about a half hour to swallow it, though. He has a really huge bulge now - and I was wondering if I can continue feeding him jumbos every week or wait every 2 weeks. I do not know how long it takes for retics to digest a large meal. I don't want him to become obese, but at the same time I want him to reach monster size. He's around 4 foot now, and I know that is pretty small for a year old retic. He was thin when I got him, but put on a little weight since I have been feeding him weekly. So should I stick with jumbos weekly or every 2 weeks? Or should I continue with the small rats?