The minimum behind your cheeks seat clearance can be obtained with Oregon Aero’s custom fit, computer cut, temper foam cushions for the Legacy. The shape of the aft spar/seat pan is more complex than most upholstery shops can fit. Several Legacies have been refitted with the Oregon Aero cushions for comfort alone. http://www.oregonaero.com/products/lancair-legacy-un-upholstered-cushion-core Not cheap, but less expensive than doing it twice.
Steve Colwell Legacy
I agree. Removing the back seat cushion is SOP when chauffeuring anyone over ~6'2"
Joe Czabaranek
Excuse me if I am telling you something you already know… but my experience is that a thinner seat BACK had a much great impact on the knee-to-panel clearance. My initial experiments with seat bottom cushion were disappoint, and then one day I modified the seat back cushion and my situation was greatly improved.