Storage has to be findable in under a minute. Rack, position, customer and condition on arrival — without that, every October appointment starts with somebody walking the racking for half an hour, and you can only do that a few times a day.
Pace the bookings against the ramps you have. When the cold snap comes everyone calls at once, and a yard full of cars with a workshop that can only turn two an hour is the worst possible version of a busy day.
Watch the age of the stock as closely as the quantity. The date code decides whether a set can still be sold as new, and a slow-moving size quietly crosses that line while sitting on the shelf.