Screw Hat Fuel % or GPM

Has anybody experimented with different ratios of hat fuel versus port fuel in a screw deal?

If so, have you found any general trends or limits? IE: Ideal range for the split as a %, or a limit on the max/min gallons per minute to run through the screw? Also, any comparisons between finely atomizing the hat fuel versus just using PSI's four case holes with four coarse nozzles?

I'd like to experiment with this in mine a bit (EFI), but before I do I was currious if anyone has been down this road already? Is there a safe low limit (minimum amount) of hat fuel in gallons per minute that a person should not drop below in terms of keeping the rotors lubricated?

The PSI manual typically prescribes 40-50'ish percent with four nozzles, but I've begun to wonder about other options......

Thanks.