how important are dimensions of tone ring cab?

[embotone]

I am building a tone ring cabinet.  My plans show a Fender Showman cabinet was 2'x3'x11.5".  My room/studio is getting crowded, I am wondering if I should try a little smaller cabinet.  How much "mojo" will I loose by shrinking down a tone ring cabinet a few inches in height and width?

[Cork]

My 2 cents,
I can confirm the OD of my single showman cab (with 15' and ring) are the dimensions you stated.
The Ampeg B-15N cab dimensions are 21X21X14 and this reflex cab also has a tone ring effect but of wood.
Sure bigger may have more mojo, but with the tone ring or reflex, I believe a somewhat smaller cabinet of this design will still maintain the ability to push air and be much less restritive than comparing the size of two non reflex cabs.
Cork