Late season, I will add a half dozen snows to the side of my 5 dozen canadas. If I have smaller flocks, I cut it back in scale. 3 dozen canadas and maybe 2-3 snows. I have had better luck adding a few white fronted geese (specks) to the side. However, the only time I do this is late season...the last two or three weeks of January. Since you are a little farther north than me, you could bump it another week forward. I do not suggest mixing the species together. I set the off species about 10 yards from my canadas mostly to block them and push them to my shooting side. If I get a mixed flock come in, the non-canadas tend to peel off and head for their own kind. That helps to get a chance at bonus geese during a hunt!