Actually a LOT more than 3" is better, in part because you will end up using this handy gadget for so many things under varied circumstances. I recommend getting as wide a range as you can (fully extended to fully retracted) centered on the middle point most common for your most used implement.
I agree 100%, more is better. But there are times when all that will fit on a particular tractor specifically the smaller tractors is a 4", 5", 6" total stroke. You need to be able to retract. He could put a 10" stoke unit on and it would work, but he would have zero retraction capabilities. it' is almost always best to have just a bit more retraction than extension from the level point of the implement.
There is a reason that I recommend an 18"-26" working length for the B series tractor. It is not just a random working length that I pulled out of the air.
A lot of people want to duplicate their factory top link. besides that is usually not possible with a hydraulic unit, I have found in many cases that the factory top link is actually wrong:shocked:, providing a working length that does not allow any retraction at all. Or very little (1/2") at best.
It is best to get the pin-pin distance with the implement level front-back and then determine what working lengths are available to best meet the requirements of said distance. Size of machine does not matter, it is all the dimensions combined what tells you what the best possible working length is.
Some examples for top link strokes. Most cat 3 hitches take either an 8" or 10" stroke unit where as the cat 1-2 Grand Ls and MX tractors take a 12" stroke unit. There are many LS tractors where a 6" stroke unit works out best.
Just my experiences, and I do this every single day.
