Good progress!
Nice to see that you are doing the throttle too. I have seen how the spark advance is connected to the magneto's (although difficult to reproduce, because it is almost hanging in the air, but I am still at a loss how to connect the mixture control. Maybe you have some additional information on that issue?
It isn't a good picture for it, but its the only one I have:

The upper control needs to be connected to the magneto and the lower is the mixture control. I may just leave it hanging there and close it up with a cover. But I was thinking of leaving it open on this side.
Nice yellow wing too. Although it may be a difficult color it looks fine to me.
regards,
Ivo