Hedge your bets by building in provision for a detachable keel by inserting a couple of threaded sockets or similar in the keel.
When I was building my paddler Bilsdale I added an extra half inch to the depth of the hull and was very glad I did so, I could have added a bit more without it being noticeable.
Years ago I built a review Caldercraft kit of the pilot vessel Cumbrae and it was perfectly stable. Some time later I got my hands on some accurate plans and discovered that the manufacturer had added a significant amount to the beam.
I wouldn’t recommend that though as it throws up all sorts of problems with locating deck houses and fittings etc. Deepening the hull a bit is easy and virtually undetectable .
Colin