LOL, yes we will give you regrets before, during and after your tractor choice.
Maybe another way to approach it is to think about implement size/width. A 40 hp engine with 32-35 hp at the pto will generally run 6' wide brush cutters and snow blowers. Drop down to a 30-35 hp engine and you would usually run 5' wide pto implements. 25-30 hp engine would be 4' wide. These are general guidelines only. 5 pto hp per foot of width. Any of those tractor sizes would pull a disk harrow to do an acre, or run a rototiller, just different widths.
There are variables of course. If you mow your brushy areas more often, just like mowing grass, it doesn't take as much power. If you let it go for two years and mow it in late July when it's really thick & juicy, it takes more power--or less travel speed.
With six acres production speed isn't your worry. Smaller implements cost less than large, you can own more of them for the same cost and do a larger variety of tasks. On the other hand, I like to say that snow storms and drifts, trees, rocks, etc. don't care or know what your lot size is. Dirt weighs the same too on large or small lots.
Three passes with a 4' snow blower is equal to two passes with a 6'. Unless you have a very long driveway that probably isn't significant. With a cab tractor keeping you comfy it's even less.
What width of implements do you envision being most useful at your place?