Going by weight and not age is going to be the easiest way to figure out the best schedule and prey size. While babies are on pinkies and fuzzies, I feed once every 5 days. Once they are on hoppers and larger, I feed weekly until they hit about 300 grams. Then, I’ll knock them back to every 10-14 days and keep an eye on body shape and and weigh them periodically to make sure they’re not growing too fast. Since yours are only yearlings, I’d probably keep them on a weekly schedule for now.
And as for this, even for a weight loss schedule with an obese corn, I would never feed only once every 3 months. Depending on feeder size, every 2 to 3 weeks is good for a large adult corn.
If you want to post pictures of any of them for us to assess body condition, feel free! 