If weight distribution is a concern, plan a hatch into the bottom of the fuse just ahead of the tail and mount all your radio equipment there. Not only will it counter the heavy engine up front but it'll give you good physical isolation from the ignition source and short runs from the servos to the control surfaces and be completely hidden yet accessable.
I've done this with two planes that I powered with Maculloch 28cc engines.
One of them was a Balsa USA Phaeton 90 which has slightly more wing area at 1576 sq. inches....but still is close in size to the Dynaflite SE-5. At any rate, the Mac flew this plane very realistically for several years and it's a bit heavier and puts out less power than the G-23 or any other engine mentioned in this thread.
Gas engines are very reliable and easy to operate once you learn a few procedures for proper setup, starting, etc.