Howdy Poppadok,
RV-4 in Houston TX. It's a bit nuanced, but yes! It is absolutely worth the time and money to install. As to clearance, I may have slightly more than 1" but not much. I don't remember for sure but I recall the track may be 3/8" give or take. Maybe someone can tell you exactly but I will measure next time I'm out there and let you know if nobody else does.
As to the nuance. The shade absolutely shades and thus keeps things a little cooler, assuming the sun is near it's high point. But the bubble is still a greenhouse and the shade necessarily cannot extend down too far along the sides. Having said that, it certainly knocks the unbearable Texas sun, heat and humidity down to bearable. Regardless, it still protects your head from direct sunlight and that alone is huge.
Added bonus is that I rarely wear a hat anymore because the shade extends just far enough forward to shade my eyes about the same as a baseball cap would. I generally keep the back shade extended just to help reduce the solar radiation unless doing aerobatics or taking up a pax.
Hope this helps!