Hey Kevin on this top-stuff let me help maybe with a cut-and-fit approach.
The woosh-poof pushes UPWARD. IF the lid/hatch system type allows twisting, or one side favors movement, then be much more difficult to evenly SELF-reseat.
You want the lid retainer to PULLED back down evenly around to reseal.
The WK sytmes poofs-release/reseating as Wayne builds them is many spaced around evenly pulling springs. This works excellent for that one purpose. He separated out the actually filling lid to a separate exprenced-skilled-hand-operation. See his working video’s.
What max and Tom have been discussing is a one-lid does ALL system. And Max with many seen earlier evolved tool-less easy-use European working systems in his experiences base.
So to begin . . .think of a man under an old style parachute. Gravity pulling the man down BELOW the evenly distributed out by many cords domed parachute “pulling” upwards. (yeah, I’ll get slammed for this one!)
Turn these forces around reversed and this is what Max wants in a good fill-lid/poof combination system.
Now with a single spring bow/feather controlled lid you are much more like a modern rectangular directional parachute. The basic lay out of the pivot and latching ends; the width/stiffness and attachment(s) to the actual lid WILL be your parachutists control.
Done right best-practices and then a fellow should be able too fuel chunk bucket/basket edge bump unlatched&lid opened. Dump-in fill. Bucket/basket edge lid flip back down& bumped relatched.
Look Ma! No hands touched. No muss.
Sure. Sure. Most will want to soft bagged fuel refill. Two hands needed and no hard edge to be your lid tools.
It’s O.K. No elegant designing and fabricating needed then.
Put on your gloves then (ha! I do) and hands-on: unlatch/unbolt, flip up/removed lid, bag dump-fill, wipe seating, flip-closed/pick up and pop lid cover back on, thump to seat, rebolt/relatch closed.
All just depends on what you want and how much effort AT WHAT POINT you are willing to put into it. ( meaning . . . A Designer/designs . . . an Operator will make any design workable . . . and bitch just how hard the Designer has made him work to make it workable)
tree-farmer Steve unruh