JGordon: I've done this twice.
Your ceiling height will be affected by several factors. First is the height of the lift. Most automotive 2-post lifts are between 11 ft and 12 ft tall. Good luck finding a used 2-post lift near you. I tried that route when I moved to the Portland area 4 years ago. Maybe one per year came up. And the buyer had to remove it. In your case, you won't know how tall it is until you get it, and I don't think you want to hold up your shop construction for that.
Next factor is how high you want to lift a vehicle. You want to lift high enough that you can walk and stand under it without whacking your head. You may not lift it to full height all the time, but at times you will.
Next factor is what vehicles you want to lift. A 911 is not tall, so you can lift it high without hitting the safety shut off bar on the lift. However, if. you want to lift an SUV or pickup truck, you want a somewhat taller lift--closer to 12' than 11'.
Since you are building a new shop, I recommend you plan for a 12' or slightly higher ceiling to allow you to buy a 12' lift. If you are building a pole barn style, the roof trusses are usually set 12ft apart, so you can set up the lift in b3tween the roof trusses, and thus lift the vehicle up between the trusses, so the bottoms of the trusses can be somewhat lower than 12'.
Weight capacity: Don't worry about it. A capacity of 7000lbs or more will lift up to a 2500/250 series pickup truck. Most of them are rated for 9000 lbs, which is good for anything up to medium duty trucks.
Minimum height: This is important if you have one or more low cars like I do. Make sure you can swing the arms under the car. Otherwise you'll have to place 2X8 boards or something to drive the car up on, to swing the arms under.
Two types: those with a base plate and those with a top cross bar. The base plate or the top bar carry hydraulic lines and cables from one side to the other. I strongly prefer the top cross bar because the top bar holds the columns in positive alignment which makes them more stable. It also holds a safety shutoff bar, so that you don't lift the roof of the vehicle into the cross bar or the ceiling. It's also easier to maneuver the vehicle between the columns when you don't have a base plate in the way.
When I bought a new lift, I bought from Greg Smith Equipment, which is now Tooltopia. Their prices are as good as any I've seen, and they have warehouses around the country to either ship to you, or you can pickup yourself. The Atlas brand they sell is from China, but it appears tough enough for commercial usage, and I know a couple shops who have used them for 10 years without trouble. A home or farm mechanic will not wear them out. Here's the web site:
https://www.tooltopia.com/brands/atlas-automotive-equipment.html
Here's the one I bought:
https://www.tooltopia.com/atexh-9kohx-fpd.html