Quarter past three

No, there is not enough compression. You must hold the prop blade when tightening. watch out! its sharpe on the edges.

Being as you already have the dowels installed.... 17mm should be fine.

Do not use a control horn for a anchor point.

You can run the antenna behind the cabin and to the top of the vertical fin or you can run it inside the fuselage or out and along the bottom.

You can not fold the antenna back on itself.

Enjoy,

Jim