Jim, if you don't install a flop tube you are limited to positive stuff only. If you don't have inverted oil pickup, you are also limited to positive stuff only.
Me? I installed a flop tube in the left tank. I don' t plan on inverted oil pick up now, but that is easier to put in later than a flop tube. I figured that if I WANT to fly upside down (at length) later, I can do inverted oil then. In the meanwhile, I can learn how to stay positive without the worry of my engine cutting out.
That's my strategy anyways!
Put in one!

CJ