For ham use they can be removed from the oil container. Either way a cheap rental engine hoist can be used. Ive used one for decades (bought it used) to remove heavy iron from trucks and also lower into the basement bulkhead door.....plus pull engines, lift either end of a car off the ground, and more.
In AB1 grid driven it is less efficient and running AB2 it is asking for trouble with serious splatter unless quite a bit of added circuitry is used. In AB1 a pair can be run with just 20W or so needed to overcome input circuit losses.
Sure - but why would anyone need two when one will do the legal limit easily? btw - running an anode-gettered tube like the 4-1000A way below ratings can actually cause problems with gas.
The sockets I've used were ones purchased from Amp Supply back in the early 1980s. They were made by E.F. Johnson; although both are in use, installed in amps, so to see if they're stamped with a P/N I'd have to take them apart, which I'm not doing anytime soon. But I think they were only about $20 each or so. As far as I can tell, only the cathode pins at the bottom and anode pin at the top really need any air cooling. I don't know that blowing air across the glass envelope does much of anything if there's sufficient space around the tube to let it radiate the heat. The Eimac chimney design seems to simply draft the air along the sides of the tube so it can escape from a smaller aperture at the top, forcing air around the anode pin seal. I use a big finned aluminum anode pin dissipator cap which helps keep that seal temperature down. Very rugged tube! The one in my 6m amp was purchased used by me in early 1984 and was an FM BC station pull when I got it for $100. That was 33 years ago and it still works exactly the same as it did then: 20W drive = 1500W output (grid driven).
It's funny. I use the 4-1000A amp on six meters almost entirely on SSB and at >1 kW output power the tube anode remains gray, it never ever glows red, so I have no idea if it's still releasing any gettering or not. But it still works fine. To get it red, I have to key-down on CW for about a full minute, and I never really do that. I think these were just really well made tubes.
I had a dual 4-400A amp that used an unpotted pole pig transformer; damned thing still weighed ~200 lbs, maybe a bit more. But I didn't build that. It was a gift from Bob Larkin, W2CLL/W7PUA. We were neighbors when he lived in NJ. He built the amp while he was an engineer with Bell Labs and then founded Janel Labs; when he decided to move from NJ back to Oregon to take a new engineering job with HP, he gave away a lot of stuff and this amp went to me. I didn't have a van or a pickup at the time, so he was kind enough to even deliver it! Several years later I also gave it away. It's probably still on the air someplace.
I think I still have a Janel 432 preamp some place. My mentors back then was Sam Harris, W1FZJ, and Henry Cross, W1OOP
I met Sam at Arecibo about 40 years ago or so. Never met him in the States, but I sure remember him. Never met Hank W1OOP but read stuff he published. "Janel" was named after Bob's wife, Jane. It stood for "Jane L." I spent many nights in Bob's basement fooling around with converters and preamps -- they were actually all manufactured there. Bob actually had calibrated his R-390A with a converter to directly read signal strength in uV on 2m. He used to give reports like, "You're 2.7 uV here." That was really funny stuff. When I pulled into his driveway once while transmitting, he gave me a "5200 uV" report.
