I believe in not breeding anything till I get a desireable pair instead of putting together a junk pair to make junk fries then worry about culling. Because the best one from a junk pair is still crap
Culling is the practice of first generation new hybrids towards making FHs in the past. For example: first-2nd generation RTs or first few generations in the beginning steps of creating a FH strain by breeders.. Those will give you many whack fries that no one would want so culling would need to be done.. But these days, if you put 2 established FH strains together, I dont think u need to cull them as they would probably look better than a non-ready strain years ago at the start of the fh hobby. Fhs have more room to look how they want but with RTs it can be more specific and narrowed down so maybe more culling with RTs.
For me, I don't like to cull unless they are defected and under an inch. Only RTs I can tell quality at around over an inch. FHs are unpredictable.