Have a look here
http://r-type.org/articles/art-101.htm
Its a very nice amp with all the details. 5B/255 is a "modern 807. No mods needed. The EF86/6BK8 is probably too much gain for todays signal sources. A single triode would probably be enough. A 6C4 or similar. A 6C4 is half a 12AU7 in a seven pin bottle. Depends on what preamp you will use, if any.
Anyway, its my way of helping you along.
Joe