That is the advice but so far I don't see an issue with my EFI 8 stack. I mounted it low. Even with the bottom of the tank.
I am using a current service fuel pickup/float sender for supply and the original supply, as the return. It works well so far.
I had tried using the tank drain as the supply port but was uncomfortable with how low it seemed even with a banjo and fluid bolt which in that thread combination really needs to be searched for. Plus because of the contour of the bottom of the tank, it really needs a very long banjo which I could not find in that size.