That there is the main issue with most of these hubs. They have HORRIBLE 5v regulation. As soon as you turn one Moonlander on you see voltage drop to 4.5 or lower. Most of the generic hubs you can't do much about, but at least these style high power hubs come with a 5v PSU that can be adjusted for the non faint of heart.

You can open up the eyeboot style hubs and inside you'll find the PSU, that has some sort of pot/adjustment screw for output voltage. The moonlanders themselves can handle up to 5.25v on the input, so lets say the hub is dropping from 5v to 4.5v when you start it up, you could set it to 5.25-5.5 on startup, so it drops to around 5v. A .5v increase will reduce current draw by 10% (so you can run existing sticks 10% faster, or add 10% more sticks per hub).

If you do this make sure you don't keep the stick idle for too long, as anything above 5.25v could damage the UART chip.