On my 1700 when measuring from center of the hole at the tractors end to parallel just over the lower lift arms ball' joints it is 19"
I would think this could be the starting point of determine any tractors top link length, Now add 5" to extend totals 24"
OK starting over, Now take 5" from 19 = 14" OK if you have a 14" top link and adjust it out as far as it will safely extend you'll have 24" This leaves approx 1.5 inch of thread in both ends, ( at least does on the top link I have) Of course I haven't got an implement that requires a full extension of 24",
The Disk harrows is what I currently have connected and I use it parallel to the ground with the link at 19".... the Bush-hog cutter I'll extend to about 22" .... the box scrap I'll pull it into about 17" in order to get the teeth to dig good, The only thing I ever had which required the shortest position was a Boom pole, having the link short will extend the boom higher,