Check the centeres of effort. Staysail ketch is just unusual enough that someone may have rerigged her and your trim problems could be right there. I assume your boat could be about 20 tons or so. Get yourself close hauled and have them move in a pack from the area of the mainmast. I'd bet on moving them aft first.
Bigger bowsprits are nice.
My marco polo has about 6' out there that LFH never drew and I am certain it imporved the boat. The bad news is taht weather helm involves mor than simple sail area. I'll assume you've checked owners' groups and the like. You want to diagnose before you fix. Check the centeres of effort.