A crude rule of thumb for 3 blade props is if your boat runs well with a "Z" size 2 blade propeller, then if you want to run a more stable 3 blade prop, you need to prop down at least one size if not two. I.E; x640 2 blade is working good, then try a x437 3 blade.

Something like that. Sometimes in rough conditions going down in size but using 3 blades can be faster and more stable, the prop isn't out of the water as much and the torque effect isn't as strong.