Most generators are 120/240V, so it is really putting out 26.5A on each leg. So a 30A 120/240V (4 wire) inlet would be sufficient. There are many ways to install this. But if you're putting it in that 200A feeder, it needs to be rated for 200A. Gives you the most options, as all of your breakers could be run from the generator. You'll have to watch your load, as you only have 26 amps per leg to work with -- won't be able to run a whole lot at once.