This is definitely a >

and ??? issue for me. So pardon my thinking out loud.
I'm trying to build an all-TOFC train typical of the early '70s: 89' flats with 30-40' trailers. Except for 4 Con-Cor flats on the bench for detailing, I have a boatload of MTLs.
Problem I'm having is mounting the trailers reliably enough for club running. You know, where you're in situations where the track is not flawless and mirror-smooth like on your own layout

, and the too-frequent derailment litters trailers everywhere for your ham-fisted buddies to "try and help", but they break-off the kingpin stands and landing gear on half your fleet? I want the trailers to stay on the flats for nearly every situation save falling to the floor. But without permanent attachment.
Yeah, I know that some glue them on (white glue), but my preference is to mix the consist up a little without a trip to the workbench. Just in test fitting I've already run into bugs with Athearn trailers (for example), where the kingpin is slightly too big for the stand. So if I ream out the stand for the Athearns, the handful of MTL trailers will suddenly be too loose. Then there's the need for something other than gravity to hold the wheels down.
As if I need another project, I'm entertaining the possibility of cutting off the stock kingpin nubs on everything and doing my own design, possibly a cheesehead screw as a kingpin and tiny neodymium magnet under the wheels for a matching bit of steel on the car. That's a lot of work, tho', when in the end we're talking 50-60 trailers.
Anybody else have a happier solution?