What would be nice is a 50 amp 240v sub panel inside the shack the split 2 20 amp 120v circuits and one 30 amp 240 circuit.
You will never use over even 10k. This 50amp thing must be another ego thing. Two separate 15 or 20amp circuits for 120 and a 20 for 240is more than enough.
I have to say that for once "Gulp!" I agree with W8JX.
A separate 50amp 240V panel is just overkill. I have 10A 120V breaker from the house panel that feeds my Radios and tons of other equipment and I have a 20amp 240V Breaker that feeds my 1500W amp and the rooms split AC system. I have never had a problem even during 10 hour runs during contests.
The downside with going too big with the breaker and wiring is that it's going to take one hell of an incident to trip that 30Amp 240V breaker, it's better to keep the breaker a bit closer to the normal load and not going insanely overboard.
I used to think that too. Then I did some pricing when I ran out of outlets and found in the long run as you add things, it is lower cost overall to have had a sub panel during the new construction then to keep making new runs back to the main panel.
Then there is the convenience factor. I like when my breakers are right where I have a higher possibility of tripping them is really handy. Running to the breaker panel after tripping out all my outlets because I used the multi-wire method just seems silly. (I would have it wired correctly, not like JX.) And just that alone was worth the extra $50. And saved me hundreds the 2 times I needed to add a new circuit.
It also really isn't about how much power you use. It is more about circuit distribution. 200A is overkill for most houses because how many times do you draw even close to that? Same with a sub panel where you will distribute several loads. The total capacity you may use may be less or even much less then what you use. But with outlets on multiple circuits, there is less that will die when a breaker does trip. Another convenience factor.
Besides you don't run your amp at 287 watts when that's all that is needed when you have a KW. That is overkill too. So by that way of thinking there would be little market for legal limit amps. But they sell 'em all the time. So why is making electrical service more convenient any more of an overkill?