The issue with jumping pistols for height is that instead of getting stronger and jumping higher, you may just be tucking your legs up higher. Plenty of people can do a 36" box jump, but few have a 36" vertical jump. I guess it's one of those things you have to measure by the "feel."
An even more important thing that occurred to me just now... I only have 12" of clearance above my head! Hahah. I guess these will have to be done outside.