I think it depends on a few factors:
1. How much your overflow can handle.
2. How many watts you want to burn, as someone has their return as water circulation also but this will burn quite more wattage for the same performace as powerheads so it's not good idea of doing this.
3. IMO, 4-5X return is very good, the rest of water flow should be from circulation from powerhead.
4. Your setup, like skimmer how much they can handle, example if skimmer can only handle 1000Gph you don't want to put 3000Gph through.... or someone has fuge/sump combo and wants a right amount of flow for the fuge.
I'm sure people here will have better advices for you.