If you're on the east coast (or close enough to it), you should think about going to the Army tuba/euph workshop since a number of vendors are always there. You might also try contacting some of them ahead of time to see what they'll have available or be willing to bring. And in addition you might be able to find someone there (or arrange a meeting) who has a model you're interested in trying and is willing to let you toot on it for a while. Finally, it's just a GREAT experience. Unfortunately, it's not until late Jan.
https://www.usarmyband.com/tuba/index.html
Gary Merrill
Wessex EEb Bass tuba (DW 3XL or 2XL)
Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
Amati Oval Euph (DE 104, Euph J, J6 euph)
1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
1947 Olds "Standard" trombone (Olds #3)