Hi Jason

Sorry for the delay in replying, I was away at a show in the USA.

In answer to your queries, please do not round off the edge of the hex stock. Also, please ensure that you use a starter motor, NOT a drill to start the engine. A drill does not turn fast enough once the engine starts and this can damage the engine.

With regard to the propeller, the smallest APC we have tested and recommend is a 14x14, but a 14x13.5 would probably work okay.

I hope this helps. If you have any queries, don't hesitate to contact me.

Best regards
Laurenne