Although I stuck to the plans on my -14A, I too dislike intensely the MS21042 metal replacements for AN365s for a number of reasons:
- The drag torque is much higher and more variable than nylocs, so I keep having doubts if I put enough strain on the bolt. Some folks try to measure the drag torque with a small analog torque wrench to add to set value, but I find batches to differ quite a bit in the amount of "squeeze", so I just grudgingly follow Ch.5 guidelines for nylocs figuring they aren't falling out of the sky.
- Different wrench size for bolt and nut. Need four instead of two wrenches/sockets lying around when figuring out how to access a difficult bolt.
- Most 1/4" sockets can't reach all the way down--they bottom out on the bolt so the top of the nut gets mangled, must add washers etc.
- Much more difficult to handle with gloved fingers, starting the thread blind and so on.
- Open 1/4" wrenches feel too loose on the squeezed flats, likely to strip if not careful.
- Not immediately obvious if the nut has already been used and should be thrown out (but it matters less than with nylocs I suppose).
- More expensive to replace, $0.22 vs $0.13 apiece from Spruce.
- The aforementioned corrosion doubts.
For firewall-forward stuff AN363s don't suffer from most of these issues, but they are more expensive for some reason and a bit heavier.