i know how to lower the front end but not sure how much height difference if i go one spline on the outer or inner only.

hey mate.

browse back through the old posts i know heaps of people have asked about lowering type 3's so you might find leads in there!
cheers
aaron.

Check thesamba type 3 forum They have a sticky on tech items, with heaps of detail on what you're after.

G'day mate. I saw something on youtube ages ago...it's a tutorial in several parts from memory.