I have seen a lot of mention that if you call Dillon they will talk to you about the details of the instruments.
With these old Eb tubas beware of one really critical thing: pitch. It is possible, or even likely, that the horn is not pitched to A=440, but something higher or something lower. If it's lower, then it's fairly simple to change it by cutting the horn. If it's higher, it's POSSIBLE to change it -- but that requires replacing a lot of the tuning tubing and is almost certainly not worth the expense or the effort.
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)