One thing you could do is the Full Monty.
Have some covered bays with Trackman units and then on the grass outside have Trackman range .
This is the best of both worlds.
its only $$$$
It so much depends upon your clientele. The younger generation are rapidly becoming shot information dependent in the game improvement, and whilst I dont consider it essential it certainly helps folk who enjoy working on their game.
If the range is more of a warm up area before play, with a more mature generation as its primary revenue source, save the money for a single unit and have booking times for its usage.