> Is it possible to change the rules from the
> default to something else (eg. B36/S125)?
I can't answer your main question, but I just tried
that rule in Golly 2.0, and it is pretty boring,
stabilizing rapidly. A fun rule instead is B37/S23,
which stays interesting, without, mostly,
stabilizing (at least within my span of patience) if
started from a good sized half-full random
rectangle.
FYI
xanthian.