The best free-standing, single in-bay location I’m aware of generates sales of around $200,000.
However, a 1,000 or 1,200 SF building looks pretty small when nothing else is standing around or beside it.
So, don’t go cheap or people won’t use it.
Next,
“My thought is to be on every side of town without a huge investment in multiple bays at each location.”
This is a different location problem than solving for one site.
What makes for a good single in-bay site? Typically, a small, irregularly shaped piece of land that is not suitable for most other retail purposes.
Without competing land use, such property has very low intrinsic value making it good candidate to buy or lease.
If the site has sufficient market potential, location decisions are needed for store size, layout and implemented services.
If the goal and objective is to develop a network of stores (every side of town), the first level of decision making involves investment model and network expansion - how many stores to build, in what period time and where.
If the zone of influence is viewed as a box with four sides the problem becomes could the market support four more stores, one on each side or quadrant.
If so, is single in-bay best business model to accomplish this?
And so forth.
One of the sites the mentioned guy in Florida has is shaped like a piece of pizza (V). I’ve been told this wash does pretty good.
I also know a single in-bay site in county north of me, that doesn’t wash many cars.
Principal difference is market. The county north of me is known as $3.00 carwash market.
People don’t have a lot of money, lots of car washes for sale.
Hope this helps.