I understand the reason for wanting a system which may only require one treatment etc... and a touch-up here and there. But, I have always done the old oil spray from Ontario Stop Rust ( Windsor Ontario) for over 25 years now. I let them tell me what combination of product to use and where ( standard / dripless) figured they have seen enough to know. For about $100 , I only do it every other year and have NEVER had a rust issue. If it works, why try and fix it ? Just let your car sit on the road for 4 -5 days then, wash it looking for any surface with extra oil seeping from drip holes.
Wife talked me into buying that 12 volt system in the new Chevy Trax bought in August. Guaranteed for life against any rusting but, again why fix what was not broke ? But, it is her car, we will see.