If your asking me if a 60size engine will work
than the answer is yes. The senior is a light plane for its size
and thats why they recommend a little smaller size engine.
I have flew a senior with a saito 72 on it and it done great
and even balanced out great and yes it had plent of power. LOL

Theres not much difference in the arf or the kit as far
as the structure goes. But i like to build kits. But than
again iam getting old by the day and have consider
looking at the ARFs.(Maybe some day) LoL