A pump always helps!! I have inverted the Saito and the OS .91 and .70 without any of the problems you hear about. I just set the center line of the tank even with the center line of the engines carb. So far no loading up or flooding.
It takes me A while to get the engine tuned just right when inverted though. I set it up on the ground then fly it A little, land and adjust the low end A bit more until I have that sweet spot. I keep the low end just at that almost too lean spot.
To date I have never had A dead stick or load up and I'm not A needle twister. I get them set and leave them alone. Come winter I may have to fatten up the high end about four clicks.
Before inverting I make sure the engine has been broken in and not just on A bench. I used to use A big Cub but have started using an old Kaos for this. Once broken in correctly they are easy to tune and you aren't chasing the needles.
I like my pumpers because I can install the fuel tank anyplace I like so I set them right over the CG. That's why I prefer OS and YS over the Saitos but the Saitos are great engines.