Umbee questions?

About a month ago I got a few (7) of the 1" umbee fry animal guy was selling. All are doing well and the smallest is around 2". I did a search for threads about umbee on here and didn't see much about the actual care for grow outs. I've been doing weekly water changes of 40-60% and feeding 3-4 times a day. What would be the best water temp to grow them out at? What are the best foods for optimum growth? At what size should I begin to worry about con specific aggression? At what size will I be able to sex them and what are the identifiers for male and female? I'm hoping for a male, but a pair would be even better. Once they are large enough they'll be moving to my 300g.
Thanks in advance for your advice.

Thank you, Right now they are in a 40 breeder that is planted, AC 70 filtration with a surface skimmer and has a large air stone. Temp has been 82 since I got them and I have been feeding a variety of pellets, cichlid gold, nls, crushed massivore and frozen brine shrimp. Now that they are bigger I've also added giving them red worms that have been cut up for easier eating. The reason for not starting them in the 300 is they are still small enough to get through the teeth on the overflow and end up in the sump. Once they reach 3-4" I'll move them to the 300g which with the way they've been eating might be in less than a month. I'll up the water changes to twice a week to be safe. So far parameters have been good, but they are getting bigger thus producing more waste.