Kyosho made a spit that was 90 size. Compare the wingspans and compare.

My preference is for aft cg around 30% range. When I do this I reduce the throws so it is not twitchy to fly. I wouldn’t recommend forward of 24%. Forward cg requires higher airspeed to land and increases the chance for nose overs.

as recommended earlier, measure from leading edge to trailing edge at the fuselage and multiply by the percentage of cg you like. Don’t worry about the wing taper, this will be close enough. 25% is close to most manufacturer cg