I can make measurements tomorrow of the chair. The footrest (really, a stretcher) can be used depending on how you want to sit; I rarely use it as such.I'm starting to wonder if this is the right approach. How high is the seat off the floor? Do you use the foot rest or is it just for stability? I guess if one goes this route, the seat level must be perfect since it's non-adjustable. Is the padding thick enough? Lots of reviewers say you need about 3 inches for comfort. Plus no padding on the back, which seems more suited to mid-upper back versus the lumbar area.
P.S. Nice 15/6's from Don! He made several cabs for me, which brings fond memories of gigging those for a few years during the Dave Green(boy) phase.
The LDS cabs are 10/6 (I calls them a 1106); note that they are mirror-imaged. Eminence 3010LF, FaitalPro 6.5 mid driver that works well up to about 10K, and a custom Ralf Patterson crossover.
For me the Nitro works well for upright as well, and they make a taller Lunar Tympani throne with a footring and backrest, but it does not break down.