While the ten-minute rule is commonly used, it relates more to not over feeding than best practices for growth. Growth is different by species. BG/RES etc. have relatively small stomachs. They grow better with smaller feeding amounts several times a day (during growth months). FH and GSH are similar. LMB, SMB and HSB can eat once a day and maintain good growth. All of this is supplemental feeding info and assumes there is enough natural food.

Your results noted seem on course - keep at it. Fish vision is not exactly like ours (2 eyes on the front focused for binocular vision). Fish often turn their head from side to side to get accurate size and distance info. Also, it is thought that fish have different color vision (light through water) and may see in spectrums that we can't.