To be honest, I've been perfectly happy with my 23" and never considered a 2nd KK. Back in the day when I had the POSK, I did get the small Grill Dome, thinking I'd waste less charcoal cooking smaller meals on it than the bigger one. Since I've owned the KK, which is about the same size as the old one, I never use the baby Grill Dome. Also, at the time that I bought my 23", it was the biggest one that Dennis made.
All things considered, I'd probably stick with my single 23," but I do appreciate the versatility of the 32".