I tried several LED replacements for the 194 bulb. One had a plastic sealed cover that I cut off to "make it fit" but those weren't bright enough for my satisfaction. I tried, like you, several types of LED's from Amazon and EBay without finding an assembly that would fit "under the clearance light cover.
Then I ran across these:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
They aren't "Perfect" because they are "ultrabright" meaning they are "bluish" in color and appear "not exactly the same color" under the yellow clearance light covers. But, they fit, they are bright enough to be seen clearly and once all the trailer lights are changed out, the color difference is negligible.
I used a little di-electric grease (silicone grease) on the base of each LED assembly to help prevent any corrosion. They have been installed for about 4 months now with no problems.
As for the "dead links" and frustration finding acceptable LED assemblies, as rapidly as the electronics industry is "evolving" (read: changing) these days, it's a wonder any of us can find an identical replacement 6 months after purchasing an electronic item.
I think that you'll be satisfied with these in your clearance lights. Post your opinion if you do order them. Good Luck
ADDED: Most LED assemblies are polarity sensitive. They won't work if plugged in "backwards". To help get them installed properly without the hassle of going back and changing them if installed wrong, on your trailer umbilical, jumper between the two pins immediately next to the keyway. That will light all your clearance and tail lights so you can make sure the LED's are installed correctly "the first time up the ladder".....