[gregbradley]

Great thread, some valuable advice there.

Another view on this. As a contractor I always prefer to measure to the acutal rather than the theoretical. Working on a few building sites will teach you that lesson very quickly! What something should be versus what they are can be 2 significantly different measurements.

Keep in mind these models are exactly that - theoretical not actual. They are a computer generated of model of the mounts performance, not the actual mounts performance.

So in the case of yours where there is disagreement I would check the actual performance of the mount. If you autoguide as-is and check the guide errors in a few spots. Then take one of the model's suggested improvements and the autoguide again. Now its a simple case of are the guide errors on average (not just one guide star) better or worse?
Now you are checking against the actual and not in theory land.

As the lowest possible autoguiding errors I assume is your target, then this should be the measure of what you judge against.

With T-point you also have to make sure you get rid of outliers in the model before you do the polar alignment assessment otherwise you are adding in noise to the model and it will skew the result.

I found T-point able to get me very close and once I was getting round stars routinely I stopped at that point even though a further tiny tweak no doubt was possible.

Greg.