I know I saw a chart somewhere

Can anyone tell me where I can find a chart that lists average weights (body weight) and what spring to use?? I have a 97 KX250 that came stock w/ 41's. It seems that the guy I bought the bike from replaced them with 44's. I am 5'10" - 180lbs. Seems as though if I remember correctly I should be using a 42. I just want to try and get things as close as possible for this spring when I start riding it and see where I am at.
Thanks for the help-
Evoboy

Thanks for the reply's . . . I do plan to try these out first before anything else, but I thought I would look at the chart just to refresh my memory.
Thanks again-