Here you go on the Prindle rudder gudeon line running. Use the strongest, non-stretch, 1/4-inch lines you can get. That's 1/4" for stock! I'm going to post links to the pics since they're fairly big in size. You can just download them: Prindle rudder gudgeon line pic #1 Prindle rudder gudgeon line pic #2 Prindle rudder gudegon line pic #3 Prindle rudder gudgeon line diagram
The raising line goes out the top of the gudgeon casting so that it can be pulled back on the slot to act as a cleat. You can make that line long enough and tie it off on a snap-shackle so that the two rudder raise lines can clip together. This way to raise the rudders, you can pull on one line for both and use your feet on the rear crossbar for leverage. (I don't. I have them separate and tied off on lawnmower pull handles. I just raise each one individually.) The "lower" line can be shorter and you can tie them off on lawnmower handles. They don't take a lot of force to drop the rudders down and have them lock in place.
Make note of the line running in the last diagram. The raising line goes over the outer wheel, down over the FRONT of the white nylon bar, back over the BACK of the inner wheel and ties off in a knot inside the rudder. This way as you pull on the line, it first pulls up on the bar with the white nylon guide around it with the springs. This releases the rudder lock. The springs hold it down on the lock, the first tension to raise, raises the bar up so the rudder can then come up.
The lowering line simply goes over the middle wheel, down BEHIND all the bars and out to the rudder where it ties off in a know.
The tiller crossbar bolts should go THROUGH the two rudder lines. If there's slack in them, they'll move to either side to let the bolt go through.
Make sure to properly adjust the length of the rudder lock-bolt. You can adjust the rudder rake. The more rake on your mast, the more the rudders need to be raked forward. Most Prindles will want their rudder lock bolt almost all the way in as far as possible so that the rudder is raked fairly far forward. If it's in line with the stern or raked slightly aft, the boat will have lee helm and always want to fall off the wind. It will also make the helm real hard on your arms. Locking should be tight enough that they lock in, but with a hard slap of your hand to the front of rudder blade, it should pop out. This'll prevent grounding damage to your rudders.
A lot of the rake setting and stiffness setting you'll have to play with to see what works best for the boat. They all have a mind of their own.
Hope this helps.