I did include a GE 5998A with the loaner amp I am sending out as well as a black glass round plate Tung Sol 6sn7. I also included a grey glass Tung Sol but I am not certain of the plate structure within that tube. There is also a 50's Foton and Melz 1578. Both are 6sn7 equivalents. I have never been interested in designing for the use of multiple types of tubes, my amp was designed to show off 6sn7 equivalents with specific power tubes.
Also like ZMF I like to make use of quality woods and make the amp appealing to the eye. I do not do metal boxes, nor would I ever, even a power amp I built had to have its own type of wooden cabinet.