Mecanim lots of clips, lots of potential transitions

I have a boxer with 8 attack animations and 3 stances.

The boxer can go from any stance to any attack, from any attack to any stance, and from any attack to any attack.

This creates somewhere around 90 transitions. What is the best way of handling this? Can I change the animation clip of a state through script maybe?

any stance to any attack, from any attack to any stance, and from any attack to any attack.

How does the Boxer look throwing a left jab when he is standing right foot forward? Probably odd since a jab can only be thrown from the same hand matching the lead leg.

I’m not trying to come across rude or sarcastic. I ask this question because - in real life a boxer doesn’t do this - he stands right foot forward and jabs with his right hand, vs-versa left foot forward left jab.
A boxer can’t transition from right jab to overhand right without changing his stance from right foot forward to left foot forward.

Could the states in each stance only allow for selective punches based on the stance he is in, All punches come from the idle animation with correct leg forward, and transition into which ever punch the player selects. and only transition to opposite punches (left jab / right jab) after changing stances.