Hi yes that is a drastic thing to do but could well be correct as to fix weather helm you either rake the top of the mast forward or you move the whole mast forward or you select a bigger headsail or reef the main. My endurance has weather helm too but only with the genoa not with the Yankee and staysail. My genoa is 100 percent I think a 110 percent one would have less weather helm.

I find with a staysail only (15knots upwards) the weather helm disappears. I have a cutter rigged sloop. Maybe your previous owner was changing to a ketch rig for that rig the mast is positioned further forward than for a sloop rig on the same boat.
Regards, colin