Two Full Desk rooftops at a time
Ten is the ceiling on the business. Two is what one person can actually deliver at that tier once the matchback and the prequal routing are running, because that is roughly sixty hours a month per rooftop and there are only so many of those.
Past two I am hiring, and what you would be buying at that point is a coordinator — which is exactly what you already have and exactly what you are trying to get away from.
If both are taken when you call, I will say so and quote you Front Line, rather than sell you a tier that fits my capacity instead of your store.