The beds in the Leopards are bigger than the MM '38. And if I recall the aft beds in the 433 are a couple inches wider than the 393.

If I were in your shoes, and I have been, I'd book the Moorings 393 and just use the extra space if the third couple flakes on you. It's bigger, and therefore probably more comfortable, but not so much bigger that it would be more difficult to handle.

Also, you can complete your sailing resume online with the .moorings and it will tell you what boats you're cleared for. Probably want to confirm with a human being, but it will get you started.