If you're willing to have a 38 Spl dedicated gun why not just dedicate a .357 cylindered gun to 38 Spl? There's no effective difference.

You'll still get gunk in it or not and will still clean it or not the same way.

There's nothing magical about the 38 Spl only cylinder other than you won't shoot .357s in it. So don't shoot .357s in your 686 and you have the same end result.