1. Cf spinners are not easy to find in the 3" sizes. Most are for bigger IMAC planes. Yes, you can save weight but really the Axi does not like the airflow into the motor blocked by a spinner. I ended up taking my spinner off. Internal temps of the motor windings with spinner were 145+ degrees and without a spinner (just a prop nut) they are 120 degrees.

2. Several of us are using the 8mm adapter with no issues