I totally agree. It's much better to put 2-3 ounces in the tail of a nose-heavy ARF than it is to add 8-9 ounces in the nose of tail-heavy ARF. You save all up weight. Also replacing the engine is a major operation. Just add a little tail weight until it's where you want it. When you get too tail heavy, the plane starts to drag it's tail around and forward speed suffers. It's also a pain to land. Move it back in little increments (add 1/2 to 1 ounce at a time).
ORIGINAL: Jack Hyde
The effect of weight added on cg depends on how far it is added from the the cg. Adding a few ozs near the tail will move the cg back as much as removing 4-8 ozs from the engine . I would tape on a couple of ozs to the fuse as far aft as is convenient and see how I liked it. That is a lot easier than changing engines and easier to tinker with to get what you want.