Before buying I'd like to know from those that have installed them if they install easy enough. I assume you can install them on the housing from the back once the gauges are removed without taking out the clear lens. I can see slipping in the two smaller outer rings through the center hole and then slightly bending the center ring to get it in it's correct position. Is there enough room at the bottom of the gauge openings between the opening and the lens to fit the rings? I'm looking at a spare cluster frame and I can barely slip 2mm of feeler gauges in there.