Stud mount rockers should NEVER loosen up.
All Ford rockers I have seen use good locking nuts, those hold on nice and tight Not the cheapo Knurled or Nylock nuts that cheapo Chevys use that only hold tight the first time put on the stud.
The studs are screwed into the heads, cheapo Chevy heads have pressed in studs, those can pull out over time.
As long as you adjust the valves properly you will have no problems. Use the Intake Close / Exhaust open method. When the intake valve Just closes, adjust the Exhaust valve on that cyllinder, when the Exhaust valve JUST starts to open, adjust the Intake valve.
With Hydraulic lifters, go with 1/4 turn past zero lash. VERY IMPORTANT do not use the spinning the pushrod method to find zero lash.
The trick is to snug down the nut till the point the rocker JUST will not rock back and forth, this is the real Zero lash. This is the point where all the slack between the pushrod, valve and lifter is taken up without starting to depress the plunger on the lifter.
The spinning pushrod method fails beacuse some of the lifters will be "pumped up" or full of oil and will feel solid and not depress easily. So when you find zero lash the pushrod will not be easlily spun. But some lifters will bleed down and the plunger will easily depress at zero lash, and you will end up pushing the plunger nearly all the way down before the pushrod stops spinning.
Having adjustable stud mount rockers is the way to go, trash the net lash pedastal mounts I can't imagine how much of a pain it is to find the proper preload with shims etc, plus the weak 5/16 bolts with 1.7 rockers icko.
Stud mount rockers are more forgiving of pushrod length issues too, but it still does pay to have the right length in the long run with any setup
I would forgive someone with a nice set of 1.7 pedastal rollers that did not want to buy a new set, but heck, you can sell em on EBAY