How about using both, I did on the first blown EFI motor I built, 35 lb per hour on top and 55 lb per hour on the bottom. That was a long time ago and we ended up removing the lower ones and switch to bigger 85 lb injectors on the top. That was 499 inch all aluminum KB street hemi block with Dart cast heads, 10:71 with a Bug or Bird catcher(3 hole ,3000 CFM at WOT), can't remember which Due to mismatch parts from BDS that turned into turd soup It ended up with a Littlefield 10:71 and Motech EFI, that worked good Good luck