Hi!
A suitable prop size for the old FOX .15 (2,5cc ) is a 8x4 or 8x5 prop.APC is a good choice.
fuel: 25-25% castor oil, 5-15% nitro and the rest methanol.

You can flip start that engine! All of us old-timers used that metod when we started decades ago
, and we still use it, using the long finger! Or...using a modern electric 12V starter.