There are a lot of TBN authors that know a great deal about tractors and I like reading their posts. No doubt they forgot more about tractors than I know. With that said, I don't necessarily agree that number of acres dictates tractor size. I would think it is what you are going to do on those acres and how many acres you are going to actually work.
When I was shopping for the first tractor three and a half years ago, I was looking at the L series for our 127 acre, four member, hunting camp. Camp land is mostly wooded with about 40 acres of thick brush. Other members wanted to get the BX, which we ended up with. I was somewhat disappointed at first.
Main use is to maintain trails through the woods by removing dead fall, bush hog other trails, grade trails with the BB to prevent erosion. and cut shooting lanes through the thick brush. It is no speed demon, but it gets the job done, and I have the time.
I was helping a neighbor out the other day and he had an L3901. Jumped on the L to help to move 14 dead ash that he cut down. Great machine, but if I had the L at the camp I would be limited because of its larger size. Would be harder to turn around on the wooded trails and hard to maneuver through the woods. Would also turn shooting lanes into runways.
OP, a lot of great advice given. Get the tractor that suits your intended use on your land.