I was doing some research on what will be the ultimate 6SN7 Addict's amp. & I think it will be this :
https://www.cavalliaudio.com/index.php?p=product_details&pId=1
In my opinion, Glenn's OTL with a 6/12/25V heater switch is a strong contender for the "Ultimate 6SN7 Addict's Amp".
But then, I currently have what could be considered a poor-man's Liquid Glass Hybrid: a modified Little Dot 1+. Like the Liquid Glass, the LD is a hybrid, but with rollable op amps in the SS section. While designed to run two triodes (actually, two triode-strapped pentodes), I have added a 9-pin breadboard socket and a continuously adjustable (up to 25V at 4.5A) DC heater circuit. Granted that I need to use pin-adapters to correctly reroute pins, but I can roll all the tubes Cavalli lists for the Liquid Glass, and more. For example, I have used 8CG7, 9AQ8, 25SN7, 7963, C3g and tubes from the 5687/6900/7044/7119 family. I have even ran a 6AS7 as a driver. lol. And the total cost of the LD1+ plus mods was less than $200!
But if all one wants to do is roll 6SN7's, and perhaps 12SN7's and 25SN7's, I would suggest that Glenn's OTL is the ultimate 6SN7 addicts amp, for a quarter of the cost of a Liquid Glass. And again, with pin-adapters, it should be possible to roll all the tubes listed for the Liquid Glass. (The only one I am not sure of is the 12AT7, which might have too much gain: 60.)