the thing with std regs struggling to supply fuel is a myth, dont forget the regs dont actually supply anything!

the problem with the std reg in the end, is the fact they cant get rid of enough fuel down the return line, so you end up with excessive line pressure,

imo a good guide is, a single 044 pump will be best off on a std reg,
twin pumps etc will be flowing too much for them to deal with, and you need something bigger