think you mean 17" or 18" crash?
anyway, i believe the larger the cymbal, the lower the tone of the cymbal?
anyone cfm with me this, i'm not sure, it just sounds logical this way, i suppose.
since you have a 16" crash, if you really want to hear a significant difference in tone for your crashes, why not get a 18" crash?
just working by this logic.
cheers ;D