If you read some of the threads back when we had a competition on grow outs, you'll find that moving to a larger tank with the same water change schedule will increase growth (think 55 gal). Keep pumping the food since you're cleaning out waste every 24 hours. You'll find segregation in size between males (larger) and females (smaller), and potentially 1 - 2 more runts (very small). That's to be expected with discus. If you do this again, wean them to a meaty diet within 3 weeks free swimming and they'll explode in size.
I used to have a partner raising discus. He had MS and was mostly home bound, living on Social Security and Medicare. We became good friends and agreed that I'd handle the breeding and he'll raise the fry. Since he was home all the time and hot water was covered in the rent, he would change 50% - 60% of the water after every feeding, every day, 3X a day. When discus get that many W/C's, the males and females grew out uniformly. BTW, he fed flakes. I had a pretty rough work schedule and he was always home. So if anyone wanted to buy discus, they'd called Al.
We had a rocking time doing this for 5 years before he passed away. I learned a lot of things from Al. One was that size disparity between the sexes in young discus could be overcome with large, frequent water changes. Wish I could post a picture, but that was in the analog days.
Willie