I have an antique clock weighing 10.2 kg (22.5 lb) all told. The only available space on which to hang it is drywall, and I can't find any studs whatsoever. Also, the clock is made out of fragile old wood and only has one large mounting hole, originally intended to take some kind of hook. I don't want to put anything metal in there because it'll chew up the wood. I came up with a plan involving a pair of rope loops:
The rope loops will be attached to the wall with molly bolts, each rated to hold significantly more than the total weight of the clock. I'll then run some kind of rope harness through the loops and the mounting hole in the clock. I have ten feet of nylon paracord (rated load 200 lb) to work with.
The question is, first, is this a sane plan, and second, what is the appropriate harness? Which knots, where? In what pattern should the lines run?
Note that the backplate of the clock is quite thick, 1.25", and should be as flush against the wall as possible.