Hi David, the AVO's I believe have a single adjustment but it affects both compression and rebound. There's about 20 or so adjustment positions on the knob. AVO do some billet aluminium double adjustables as well.
The Konis are very good but they are very expensive too.
Give the guys at Austrack motorsport a call for AVO prices. I've been dealing with these guys a bit and they have been very helpful. I think Ian buys his AVOs from these guys.
Austrack Motorsport
Cheers