Generally, I try to restart if there are 30-32 wolves and no support units, but 36-39 is okay. Also, sometimes I have to sacrifice individual wolves, which is critical when there are few of them.
You don't restart because it's impossible to play with 32 wolves, but because you might get more next time. If it's so difficult for a Barbarian to fight Tyraxor, what about the other heroes?
Immediately reducing the number of wolves for Tyraxor might be too much, but making it 4-6 instead of 5-7 is just right. And for the others, add goblins and 1 orc.