I have read in posts here about people wanting to get larger return eyes to lower friction loss and move more water... my pool eyes came with the eye and 2 sets of inserts that snap into the back to change the size of the eye discharge. I get that a smaller discharge would give a more powerful jet to circulate water in pool, but it would also create more back pressure.
I was thinking of removing the inserts all together to get the biggest opening I can (still with the eye face on, just without any little cones to make it smaller). Any reason why I wouldn't want to do that? Actually, I was thinking I might improve the efficiency of the entire system by removing them.