Hammond 1750E instead 1750H

That's a bit of a tough call as I read Mark's page and he said he just used whatever he had laying around, so this is kind of an oddball. I would try to get it closer to 15 watts. Generally, as you drive power tubes harder, the pri. impedance goes down, so he probably thought 6600 would be better because of the higher power/voltages for this amp. You do have -54 volts available for bias, so you could replace the bias trimmer with a 20k to get closer to that full voltage if the 10k he has doesn't do it for you since he already has -45 for 20 watts.

There are no voltages given for the power supply, but with SS rectifier and 325-0-325, for the main AC out, you will be well into the 400 volt range for the voltages on the 6V6s. It might be hard to get this down to just 15 watts at these voltages. It depends on how much extra bias voltage you can get.

Also, down below the 6V6s, there is a note that says 18 Watt transformers can be used which tells me that 8k will be fine also. It's kind of your call. It's marginal if you need to get it down to 15 watts but will be better for your OT since it's rated for only 15 watts. I suppose it depends if you are planning on cranking this amp up a lot or just messing around. This too will help to decide.

A final note, I looked up replacement transformers where I get my supplies at and they have the Deluxe Reverb tranny at 6600 ohms and these voltages should be close to what that amp has. These voltages are really pushing what a 6V6 will take. Get a good set.