Super 225 timing settings -

So I have my 1966 Valiant tuned up to factory settings - 2 BTDC and 650 RPM at idle. It has electronic ignition. It runs great, nice and smooth. I get about 20 MPG with straight highway driving. However, the acceleration is lacking. I have seen recommendations for settings all over the range, but I am looking for economy with a little more power. What timing setting will give me that? Thanks for the replies.