Originally Posted by Parker
19cm doesn't seem very full cut, toasty. seems fine for slim soles.
generally I like slim profile shoes with narrow pants, and chunky shoes with wider pants. but there's always exceptions. e.g. a beefy longwing or boot can look good with narrow pants or jeans. kinda depends on the style you're going for too.
I think that it's even more than that. Dark shoes with dark pants is quite different than a lighter colored, contrasting shoe, or a dark sneaker with a contrasting sole, or a light sneaker with a light sole. It also depends on the weight and drape of the pants. The same hem in a 18 ounce dark denim is going to look very different than in a lightweight worsted wool. And again, you can be going for a very balanced look, or for a deliberately unbalanced look. And of course, some guys can do some things that other guys just can't. I've seen some dudes do very slim shoes with really baggy jeans, and look great, in completely different ways. One guy is a huge guy - 6'3" and really V-shaped and muscular. The other dude is much smaller, so much so that the jeans looked very oversized, like trousers cut in the 1920s. I tried it, and despite getting some (genuine) compliments, I still felt stupid. So after a few hours, I changed, and that never happened again.
While guidelines are useful as just that, at the end of the day, you'll have to look in the mirror and see if it works for you.