I've used a 24" high with 8 panels 24" wide each at
http://www.midwesthomes4pets.com #540 in gold color and I wish I bought a plastic one for babies instead of this heavy duty metal one. It don't sit well on a wooden floor, ok for carpets. It folds flat to carrying, but is really heavy. Our 2 have never tried to jump over being 5 lbs each fully grown. Now its only being used as a room divider when I want the living room closed with a wide door opening. Comes in handy tho ! I'd be on the safe side and get the 24", you can still reach in ok.