No disrespect to those using a thr-rudder mix, but I disagree with the posts that say you can't trim with thrustline only.

I have done it both ways, and I find that a thr-rud mix does not work correctly across all speeds, and if you have it set to work at the top of an upline you will have a model that yaws to the right on high power level flight. I was never able to eliminate this and caused more work for me when flying faster than where the mix was set to work. If I set it to work good across all horizontal speeds, then it was not enough for the vertical.

Spending some time to get the balance between rudder trim, and right thrust you can get a model that goes straight up to the top of the box, and flies straight on high power horizontal flight. It takes some time, but IMO provides a better flying model. I flew with a thr-rud mix for over a year, and went back to not using it as I was never able to get a satisfactory setup from it.

I also don't use the left mix at idle, I have never noticed a tendency in my planes that would require this mix. I have tried and tried to see why its needed, and even put a mix in just to see what it does, but I really don't get it