Not sure if this is the right place for this thread, but...

I know you can change the horizontal diameter of a brush in Photoshop, but is there a way to alter the vertical diamter also? Reason I ask is that I want to put a border around a map, but the one I want to use won't scale correctly. Is there a sub-menu I'm just not seeing where you can type in the exact dimensions you want the brush to be, like 700 by 300, or whatever?