For my 1924 Eb Buescher, I have to use something else. It really drains condensation through the bottom valve vents, but unfortunately doesn't have the nice slotted nubs to hold a real gutter. What I've done in that case is to take a fairly large diameter (1" or so?) length (4"?) of vinyl tubing and split it lengthwise. Then I cut a similar length of SOFT sponge about 3/4" wide and use the vinyl tubing to hold that up against the valve bottoms (the edges of the tubing kind of "hook over" the bottom valve caps. Not as slick looking as a real gutter, and a bit messier to attach and remove, but it works.
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)