I usually recommend a cheaper two stroke for a first engine, like a 46 LA for that plane, because sometimes the first plane that someone flies gets beat around a little. But in this case, the Senior is a slow flying and very forgiving plane. So I think it would be OK.

My second plane years ago was the Senior powered by an Fox 40. I added ailerons and it was a great plane.

I taught a student on one a couple of years ago and it was powered by an old ST 40 (round head). It was the red ARF and we nicknamed the plane the red zepplin because of the way it flew. A couple weeks after he soloed and felt comfortable with it he was attempting to land. He got backwards on the elevator and nosed it in from about 5 feet up. The only damage to the plane was the nose gear mount broke off of the firewall.

Once you get infected with the 4 stroke disease you will never be the same. The tach is very useful and I find they are easy to tune and hold settings better than my 2 strokers. The only thing I don't like about my smaller 4 strokers is that they are harder to hear when multiple planes are in the air, especially the big gassers. The only time I deadsticked a 4 stroker was when a valve keeper broke on me and the valve dropped into the engine. Just keep in mind to adjust your valve on occasion.