online tournament for Heroes 3.

In any case, no matter how much you try to balance things, you can only test it through experience. So, major changes and balancing can be done after playing the first round. I think all the shortcomings will immediately become apparent, and it will be clear in which direction further work is needed.
And yes, I would be glad to see you at the tournament, if, despite all the awkwardness of what I said, you still want to participate in this event.