Have you looked at the single ended articles Ken wrote for Vintage Guitar magazine?
I use to have them somewhere, I'll have to look for them again.
I suppose the question to be asked is what is the real thing. A 5F1 Champ, a Princeton, a Blackface Champ, and then there are the Gibson variations which aren't to shabby either.
The Champ mods are also to be considered too. To build a DLM you will need a transformer set that is better than the stock Tweed Champ set, otherwise you'll blow up output transformer and power transformer will run hotter than your output tube.