Martin is just starting back up again. They had some issues and think they sold to a new owner last year.
Your best bet it going to a pro shop. You can get measured for your draw length, but everyone is different.
Draw weight, you're going to have to start probably around 40-50lbs. You can be a big strong guy, and 65-70 would be tough to draw. Just because it is utilizing different muscles, but if you shoot religiously, and a lot of arrows, you could jump up in weight pretty quickly.
Ata (axles that the cams rotate on, at the end of the limbs) is kind of going to be dependent on your draw length.
Brace height (distance from the throat of the grip to the string at rest): you are probably going to want to start out with a 7" or so. But do not get caught in the speed hype. It is nice, but you don't have to shoot 300+fps to kill an animal.
This is just the tip of the iceberg, just don't get addicted like me lol