Nice choice JT. All the Sig construction manuals are quite good and easy to learn from, my suggestion would be to follow it carefully without to many mods like the cowling but thats your choice. My first question would be is this your first trainer or do you already have some flying experiance.

A sixty two stroke is an excellent choice for this airplane with plenty of power reserve but not to excess either. Its actually one of the more popular size engines to use with this airplane.

John