Estimating forklifts/technician ratio makes sense specially when the company is developing or growing.

It's a matter of calculation, whether the new guy in a new area is able to return the costs and bring some money, or if the existing guys are able to preserve the proper quality of their work and need some reinforcement.

In my company we base upon the technician utility factor.

There are about 1700 working hours a year.
The average truck we maintain (90% they are Linde) works 2000 hours a year and this requires about 25 labour hours of service technician for inspections and repairs on IC trucks and about 15 hours on the electrics.
So, statistically, an average truck requires about 20 labour hours a year.
With all the time losses, an average technician is able to deal with about 70-80 statistic Linde/Still/JUngheinrich trucks.

Of course it may vary depending upon the fleet, brands etc, but when we create the new service technician position we consider this factor as a lead.