I sail a similar design boat. Weather helm also (perhaps principally) depends on the 'shape' of the mainsail and where the position of maximum draft (POMD) occurs. The POMD can be shifted fore/aft by adjusting halyard (or cunningham) tension and that will establish the amount of weather helm desired.
A woven dacron sail needs to be additionally tensioned along the luff AFTER being 'raised' to take the proper shape that the sailmaker 'designed' into the sail .... OR if the sail is aged, the luff boltrope probably has 'shrunken' ... all leading to 'weather helm.
Weather helm is function of mast rake AND mainsail SHAPE. Here's an article I wrote some time ago about how to 'properly' raise a woven dacron mainsail to obtain 'as designed' shape and 'proper' weather helm: How to properly RAISE a woven dacron mainsail - SailboatOwners.com
hope this helps. ;-)