I my self have a Graphire3 5x8 tablet, as for the settings stuff.. is it possible to download a english version of the software?
I actually found the default settings to be perfect in photoshop, odd
For adjusting the tip feel its kinda self explanintory at least.
And here is the users manual for you that I uploaded (Its a PDF in english.)
http://www.disp0sable.org/Graphire Users Manual.pdf