You can't really, you just have to use your best judgment.
For stick flex, your average-sized NHL player uses about 90 flex, 100 is for bigger d-men. I wouldn't go any lower than the 90 flex (though Brett Hull apparently used a 65 flex stick later in his career).
For stick blade pattern, I usually use the middle two (on the screen). The top one is good for snipers, and especially for smaller guys who need a bit of extra kick from their blade. The bottom one is good for danglers who use their backhand alot.
With blade radius, it's almost always 11", unless the guy is massive (6'5" and up), in which case I'd choose 13". As an aside, the blade radius option is kinda stupid, IMO, since most hockey players are concerned with the radius of the blade hollow (ie. the angle of the skate edge).