Originally Posted by Hydro Junkie

The CA is more than capable of handling the load, adding more glue just adds unneeded weight. You have to remember, wood glue isn't a structural product. For epoxy to become a structural product, you need to add other things to it. A general rule to build by is that any weight that is added after the fact is your enemy. I probably would have cut lightening holes in all the ribs to make the structure lighter but, that said, you have to be careful to not take so much as to weaken it.
As for the engine, the plane is designed for a .40 to .54 four stroke. The issue here is going to be prop clearance. A four stroke can swing a larger prop than a two, but at less RPM. To keep it loaded properly, it will need around a 12X8 prop where an Evolution 46 would only need an 11X6. To use a smaller prop on your 72, you could go to a three blade and drop it down to a 10 to 11" prop