Hideaway headlight won't stay up
 

My passenger side headlight cover keeps dropping down when I drive the car, or when it sits a while. It won't stay up on its own when I disconnect the vacuum lines. I've tried adjusting the bracket that the spring clips to as well as the other end that bolts to the cover itself, but I can't seem to get it right.

The actuator is working as it should.

Any tips/videos on how to set up that bracket/spring? The driver side will stay up on its own, so I've got that one right.

drooping when not in use is the over center spring is not applying enough tension. First thing to check are the bushings, if they are MIA the spring can't apply full tension. You can also bend the spring attaching tab on the actuator to tighten up the spring. If that is not enough you can cut a slight notch on the top of the lever arm (use instead of the hole the spring goes into) to further tighten the spring. As for drooping when driving probably the upper seal on the actuator. Does it droop or stay down when driving?

I think it falls down and stays down. I pulled vacuum on the upper side and it raised up fine, although the actuator doesn't hold vacuum, but neither does the other side.

I have a fairly aggressive cam, so it might not pull enough vacuum to bring it back up once it falls, but I plan to address that after I figure out how to make it stay up in the first place.

well, I drilled a new hole a little farther back and that seemed to do the trick. It's got more leverage back there. Now on to addressing the vacuum issue.

If the vacuum pulls it down but not up chances are it is the upper seal on the actuator, if it was the diaphragm it wouldn't go up or down. You can buy the upper seal separately. If it is a marginal issue sometimes some thick grease between the seal and the vertical shaft and the grommet area may be all it needs. The repro upper seals are quite failure prone though.

FWIW my 68 doesn't even have the tensioner springs in place and the doors stay up. (months at a time) The springs do not fit tightly.
I had installed the repro vacuum hose kit and the rubber splices with the nylon inserts had rotted a huge crack down the middle and created leaks. This is on a rarely driven garage kept car, though it does get warm in there in the summer. May be time to inspect those splices.
The rest of the hoses were in good shape. Removed those and installed a new vacuum actuator pod and it was fully functional.

There are several reasons why the doors can droop or totally drop.
(1) The seals on the actuators can be bad/not fully sealing;
(2) Vacuum Lines leaking/rotted including all connections;
(3) Lack of Vacuum integrity of entire vacuum system;
(4) Main spring worn out or not properly attached and placed correctly; and
(5) The bushings are worn out and are not putting tension on the moving parts.

Accessing all the plastic bushings requires removing the Endura Bumper. AMES sells a kit to replace all the bushings and the vacuum hoses and connections.
If you have good vacuum integrity and good springs, look to your bushings. They are the last things to check because they are hard to access.