Won't have the same effect. Even the left acknowledges that the nature of support for the two sides is very different. The pro-traditional marriage Yes on 8 side is grassroots: many small-to medium size contributions (there is a threshold below which the donations are not disclosed at all, $100, I think). The pro-gay contributions came from big name celebrities and large faceless organizations.
So do it anyway. We don’t need excuses for inaction