Shave and a haircut, whose bits?

I had a long overdue appointment for a hair cut and color today. As I sat in the chair watching my shiny locks fall into place, I wondered why in the world I had waited so long to take care of myself in this basic way. And then I got to the register and I remembered why I hate to go to the salon: the tip decision.

My appointments are always scheduled with Michelle, my regular stylist. She greets me, discusses color options and then mixes up whatever we've agreed upon. Then I'm handed off to an assistant, who applies my color, sets me up under the dryer and rinses the whole mess out at the end. After my color is complete, it's back to Michelle for the cut and style.

The bill at the end is $120 -- $55 for the cut and $65 for the color. And after I've paid it, I always stand there awkwardly shuffling dollar bills in my hands for what seems like the longest time. I just can't figure out how it's all supposed to divvy up. Michelle's the expert and I'm her client. I want to keep her happy so that she keeps me happy (you don't mess with the woman who mixes your color and wields the scissors). But truth be told, her assistant's doing about half the work. So who gets the cash?

I always walk out of that place feeling like I've probably stiffed one or both service providers, which certainly isn't my intention. But doubling the cost of my service with tip money to show equal appreciation to everyone is not so appealing either downright ridiculous. Any tip etiquette experts out there? Someone please rescue me from my compensatory cluelessness!