Not RV's, but Nanchange CJ's.
I have Marvin's injector on a DIY system using windshield washer tank/pump on a single exhaust. I burn baby oil purchased from Big Lots. I brought the injector from Marvin since before he is Smoke System Helper.
My friend has Smoking Airplanes full system with dual injectors. It is a very well made, well put together system; very complete and not difficult to install. He burns hydraulic fluid from O'Reilly Auto Parts.
We make equally good smoke, but my oil consumption is always less than my friend's - more than 1/2 less. Although there are many variables, I do think Marvin's injector design contributes to the efficiency of my smoke system.
My CJ is the green/gray one with yellow tips.