I wouldn’t do the flop tube without doing the inverted oil. I would rather the engine stop producing power while the oil pressure goes to zero. With a flop tube and fuel injection, the engine will remain producing power , and if there’s no inverted oil, the oil pressure goes to zero while the engine continues to run. With a carb, the engine quits momentarily while the oil pressure disappears, kind of nice, as no power, no damage in my mind.
If you want to hang from the seat belts inverted, for extended periods of time, then sure, inverted oil and fuel is required, but in my opinion, these aren’t really the planes for that. Gentleman aerobatics are just fine without the extra weight, complexity and maintenance of inverted systems IMO.
A big fear of mine is flying a plane with a flop tube that hasn’t been changed in several years, and has gone hard, or worse, and having an engine quit. At least on a RV, if you do one flop and one not, you have the option of changing tanks to restore power.. just something to keep in mind!