Most Ford engine rocker arms are not adjustable. The bolts that hold them on are torqued to 18 - 25 ft. Lb. Do not over torque them as that will cause excessive wear on the pivot points. When the pressure of the lifter is off the rocker arms they should feel prettty snug. If they are sloppy, the only thing to do is to replace parts using assembly grease on the pivot points of new parts which will protect them untill the oil flow takes over. You probably won't have to replace the lifter rods, but if replacing the rockers replace the small metal cap on top of the intake valve stems.
So if you are going to do it, I'd do the springs, seals, rockers and caps. The springs and seals can be replaced without taking the heads off by using a compression tool made for doing it that way, (looks sort of like a two prong gear puller), and using compressed air thru a fitting in the spark plug hole to keep the valves from falling into the cylinder. That is also done with the cylinder you are working on at TDC so if a valve does fall in, you can still grab the stem and seat it again,
(WARNING: [-X
Do not use this technique without the cylinder you are working on being at TDC. If you don't have it at TDC and a valve falls in, SORRY but you will have to take the head off). That being said, I have done it that way and if you heed the warning you will not get in trouble.
Another WARNING: plug the oil drain holes, so if you drop one of the small retainer locks they don't go down the drain. I line the area between the head and engine compartment with paper towels so they stay in the head if I drop one.
Hope that helps,

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