As far as the amount of hydraulic adjustment on that top link goes, I would like to have all I could get. What you have to determine in this case is: does the added range of movement make you a danger to yourself or others. I have, using a combination of 3PH's up and down, added to the movement of the top link, managed to bend or break some stuff a time or two. It taught me to be more careful, but I wouldn't want to give up the option of the greater range.
For instance, I have a receiver hitch built into my box scraper, and I have a 4.5 foot square tube boom that fits into it. I have use it to pluck items and carry them around. The extra lift from the top link comes in handy. I also have a winch on top of my box blade, and I have benefited from improving the angle of the fare lead, both up and down.
While I have only ever dealt with cat 1 hitches, my top link is only 8 inches of travel, and that has been enough. If I had a cat 2, I might desire more.