RE: E-flite J-3 Cub 25 ARF
Yes, you can use a full size receiver on this model. The E-flite Power 25 Outrunner with a 12x6 prop will provide plenty of power so an additional few ounces of weight are not a problem. The JR Sport MN-48 Mini Servos weigh 22.4g each as well.
I'll see how long it flies on the NiMH pack and also take a video with that pack.