If it were mine I would look at an OS .46-AX 2-stroke. This will provide excellent performance. whoever told you about the thick wing being a problem is mistaken. I've flown 40 size 3D/fun-fly planes with very thick, wide chord wings using a.46-AX and it was more than enough.

If you want to go with a 4 stroke, an OS .70, Saito .72/.82 or even the new OS .81 would work fine.

There are also less expensive engines similar to those I have listed. They may take a little more break in and there is an increased chance of getting a bad one but they will definitely get the job done too when running right.

What is your flying experience? I only ask because a Stinger is definitely not a good first plane and probably not even a good second plane.