I'm just putting together a SIG LT-40 ARF and I have a choice of a couple of engines..

An Irvine .39 or an OS 46LA. The Irvine is an ounce or two heavier than the OS.

So, how does this plane balance? given that both engines probably have similar power, would the heavier or lighter engine be better?

Reason for asking is, I just finished a Hobbistar 60 mkIII. This needed a whole load of lead on the tail with the OS65LA... Whereas my Superstar 60 balanced perfectly....