Thank you Alan.
My early model 20.3 sails so well that I'm reluctant to do this modification. The helm is very balanced on all points of sail. The only time I have struggled to go upwind that wasn't due my poor technique (I learned how to sail on this boat), was an occurrence in the Chesapeake Bay when the strong wind died out, but the steep waves remained, so almost no wind with relatively big waves made it impossible to go upwind.
Generally speaking, I don't get 90 degree tacks in the Chesapeake Bay, but I think that is mostly due to a light boat responding to wave action and/or my former poor upwind sailing skills. Using the upwind sailing tips Graham provided on this forum really helped and I can point a little higher using them. I did have to make new longer sprits so I could make my sails flatter, and I'm more attentive to my tell tails now.
Graham did a quick informal upwind test with my boat and was able to easily get 90 degree tacks (light wind in smooth conditions).
I'm sure the boat would point higher with the modification however, so it is probably worth doing. It really doesn't look that hard after you gain the courage to make that first cut, although a much easier solution would be to loan the boat out to Don next year!