Sorry but I find the debate as to the aesthetics of Barrie last with slim pants to be VERY abstract without any visuals. One guy might rock what 99 others cannot pull off and vice versa. Depends on the whole outfit, the person, the look you are going for. Then, of course, different people will like it and others won't. I guess that's obvious but I don't see how any guidance can really be meaningful without picking a specific look to put up for discussion. Maybe it's just me and my crankiness in old age.
Very true. I think the OP was asking for some general rule, but the reality is that it will depend on a lot of variables as you mention. I agree without having a visual of the OP trying the combo it likely isn't going to be a fruitful rabbit trail to follow. As many guys demonstrate, it can be done. Whether the OP can pull it off with a given outfit is what would have been a better question.