My petwash is doing OK. Great in the summer, poor in the winter. Yes it is attended, Kleeright tub (PD McLaren). I would do it again as long as you have the dedicated space and have all the services available on the spot. I would not underestimate the cost of the chems...I would not use Flee-Tick shampoo (too expensive), I would have the pet vac option. Single column vendor for treats is a good idea. Good ventilation and disinfect room daily.
I like to have as many revenue generators on site as possible...in the end..it all counts.
BigLeo