I wouldn't lower it in RDL fashion - typically people are weaker in RDL form and it puts more emphasis on the erectors that are already fatigued from the regular DL portion.
Suggestion for a solution - get a couple of small tires (from a riding lawnmower or whatever) and stand on a block, wood or whatever you have handy that will support you. Then you can do the eccentric very quickly and not worry about the floor.
Or suck it up and go to a gym. We all started somewhere, no need to be embarrased. Hell, when I started I could barely deadlift 135.