5'9" 240 here...I have a D-Air Misano for racing and track days, and I just got a Laguna 4 this year for MiniGP.
(I don't want my air system going off for a crash on one of my Ohvales).
I wear a Euro 60/US 50 suit in AlpineStars or Dianese. A 48US should fit you fine.
I have big shoulders and big legs and these suits are by far my favorite of all time.
And, I've been through a few searching for "The fit" for me.
AlpineStars makes a damned fine suit, but their torso is a smidge longer off the shelf, so the inseam/crotch is a little below
my inseam/crotch...and it binds me up on the Ohvales...I cannot move on those little bikes. It's a more extreme riding position, obviously.
My R1 feels like I'm driving a roomy SUV by comparison.