Hi John,
Sorry, this boat is way too big to consider using a single-masted junk rig, even if you take some area off the mainsail by using a headsail on the bowsprit. If you look at the Colvin-designed boats that fly a headsail, they are all two masted. You'll find the mainsail to be too big and heavy to build, to rig, to hoist and to operate once hoisted.
I found some details of the Hudson 50 at http://sailboatdata.com/viewrecord.asp?class_id=3453. The nearest boat I can think of, in terms of displacement, is Samson, in Stavanger - a two-masted schooner rig. Even with two sails, there are some challenges to be faced by a family crew.
Practical junk rig recommends two masts for under 800 sq ft, optionally two or three masts for 800 - 1400 sq ft and three masts for over 1400 sq ft. I should imagine that the area required is somewhere close to 1400 sq ft.
I think there are some powerful indications that a three-masted rig should be considered. You want a low rig, for the ICW; you need individually small sails, for a family crew to operate; you have space to put a mainmast further back in the boat than it is at present; you will find building very big masts to be quite a challenge, even though you are a skilled woodworker.
Even so, I think a two masted ketch with a headsail is just about conceivable. I don't think the mizzen placement is an insuperable problem. You could put it in a tabernacle that extends down to the keel, with a hole through the tabernacle for the propshaft, for example.