To me the question boils down to this - do want to limit yourself to positive G maneuvers only, or would you like to have the capability of exploring negative G (precision) aerobatics? You can do all the positive G stuff in an RV (loops, rolls, spins, half cubans, etc.) without the engine hesitating or throwing oil. You won't throw oil until you get around zero G. No need to go there, and IMO no need to worry about oil control in an RV if you're doing positive G maneuvers only. Low performance and slow rolling airplanes (ie. A-152) are more likely to get to near zero G while attempting positive G maneuvers if your technique isn't perfect. Easier to avoid this in the RV. For years, I did all the positive G maneuvers you can do in an RV and never found a drop of oil on the belly. Depending on the routing and setup, some are more prone to throwing oil than others.
You don't need fuel injection to install full or half inverted systems, but there's no point in installing a full inverted system unless you have fuel injection or a throttle body/pressure carb in non-FI engines. So if you want to maneuver in such a way that might make a mess of the belly, why not just install a full inverted oil system? You'll have the capability to really expand your flying and learn new skills. Cowl space can be tight, but the system doesn't add much extra weight. If you have fuel injection, I wouldn't even bother with a flop tube in the tank since it will take a few seconds to burn the fuel in the lines before the pickup cavitates, leaving you with enough time to draw short inverted (precision) lines as required in IAC Sportsman Category style flying. There's no reason to sustain negative G longer than a few seconds unless you want to do inverted spins, outside higher negative G pushes (outside loops, etc), or inverted turns. Not typical RV acro stuff.
Another great solution is Ron Schreck's half-Raven setup described and shown here:
http://iac19.org/images/DAF_APRIL_10.pdf
Engines and aerobatics
Linear Mode
