In the end, the #2.5 needle seems to be ideal. Both for mixture range, and offset (in the end, it seems the taper offset of the needle is fairly random, and has nothing to do with mixture). Also spent some nervous time with a timing light, behind a spinning prop. Very nervous work, but timing is now pretty close (gave up when all 4 ignitions were within 1 degree of each other).
It also seems that with the #2.5 needle, my engine becomes one of those that do not run well at full throttle. The last 5mm of throttle decrease RPM by 150, and swing the EGT all the way to #2 bank. The AeroInjector manual mentions this as a possibility, but it caught me out, as it did not happen with the #2 needle. I have added a throttle stop to cap the throttle where the engine is running at peak RPM.
All round, the engine is running beautifully now (although we won't mention the oil sweat from the front bearing...).
The test pilot took it for some taxi testing today. His first comment was that it 'buggers off'. He is very happy with the power and acceleration. Even 2 up, it makes 50 knots in ~200m (that was the fastest we would risk in taxi testing).
Aside from that, he was not too happy with the amount of rudder required. It is a left hand prop, and requires a lot of left rudder pressure to keep it straight at full power. We did some measurements to check the thrust line (this is a second hand engine mount, that I assume is correct). The engine mount does seem to be correct, with a healthy left offset. So somehow this little VW is producing enough torque to overcome the thrust offset, and still require a bootfull of rudder... Chatted to Carl and the test pilot, and both are happy that there will be enough rudder (if there is enough at low speed, it will only become more effective as speed increases). I will bring all my gear out to the field next weekend and recheck all the rigging - just to make 100% sure everything is OK. Will hopefully also have the AP out next weekend to finish the sign-outs, and sign the ATF applications!
Anyway, here are some videos of the test pilot taxiing the plane. My first opportunity to see the plane from the outside, looking (and sounding) like a real aeroplane!
Taxiing out:
http://www.youtube.com/watch?v=EdgxY7a-eSw
Taxi run:
http://www.youtube.com/watch?v=Pvj57nMZV8s
. The other options are to try and pull the hub with the engine mounted. It is easy to do, BUT there is locktite on the taper, and if I pull the hub, some of this dust will drop into the crank case. And then I still have to clean the taper properly, down the centre of a long bearing. Challenging to do it properly... The remaining option is one I dread - yank the engine, and redo it again...
Justin, "Rev-right Motors" says : " Ry hom reg swaer, ry hom reg !! 
$#&#$^ se enjin al lankal in n boot!! 
