I have been increasing efficiencys for over a decade now and have been spamming HV setups to boredome at this forum. HV is the way to go for decent flight times and better performance. i did even extensive research for SHV setups in 70mm edf class. It's even a good remedy for chosing the more silent"amp hog" rotors which are trending right now.
If you really enjoy increasing efficiencys you'd probably end up designing your own edf jets too
Please keep an eye on the older units. new products aren't always always an improvement.