I can agree that 24/40 is pretty uncommon, but not so with 19/22. I believe 29/32 and 14/23 setups should be completed with a 19/22 one to make sure one has a setup for every reaction size.
If I would have to use only one size setup, I would choose 19/22.
The cutest setups are about 10/20 in size, but they are so rare I've only seen two in my life.
http://rhodium.lycaeum.org (http://rhodium.lycaeum.org)
You can use adapters for connecting together the different sizes.
http://www.geocities.com/dritte123/PSPF.html (http://www.geocities.com/dritte123/PSPF.html)
The hardest thing to explain is the obvious