Hello Ken, It's been more than ten years since I've talked with Heather. From what I can recall she thought the total of Canadians that served in the WBTS was between 25 to 50 thousand. This would seem to indicate there were fewer than 50,000 Union Troops alone.

From my own research it appears that Quebec had a higher number of soldiers who enlisted in the Confederate Army followed by Ontario.

I do agree far more Canadian soldiers enlisted for the Union cause. Hope this helps and keep up the good work!