Airbrushing 4 Tigers for a Mud Run (need Help:-)

I have a sweet job that will pay for my airbrush system!

I have a friend face painter that is scaling down & is selling me her airbrush system for $1000(it's over $2000 worth of equipment, is an Iwata & has only been used 4 times).

I have 4 people wanted to be painted like tigers (arms & torso) for a mud run (1 guy & 3 girls). I'll need to learn how to airbrush & use ink, not paint, so it's water proof. I really hope I'm not biting off more than I can chew here.... but have played w/ the airbrush & feel I can pull it off....

My question is how much ink will I need (Orange, black & white) & how much time do you think I should quote for each person? I plan to line them up, do the white 1st, then the orange & finally the black (I'm not sure if I'll free hand or stencil the stripes).

Thank you!