Balancing sub-adult growth and weight loss?

I adopted my boy Tango, who is approaching two years old, about two months ago. He was being fed "1 to 2 adult mice" a week by his previous owner. I believe his sire was a big Okeetee.

After researching and engaging in discussion online, I have determined that Tango is a bit on the chubby side. (He is in between a loaf and round shape and has just the tiniest start of "hips.") I have decided to put him on a maintenance diet of one small mouse (16-18g) or one medium mouse (18-22) every 14 days. That said, at age 2, he is still growing, and still gaining weight:

July 30: 468g
Aug 18: 481g (fed 35g chick)
Sept 1: 480g
Sept 16: 490g

This seems like a good, normal growth rate…if he wasn't overweight. How does one balance maintaining or seeking weight loss for their snake when it is still growing?

May cross-post this elsewhere for advice.