In general, the rule is that the lapel width and the tie width should roughly match. I actually think, for a smaller guy, a 3" lapel works fine with a wider tie and can create a nice contrast. But that's because the lapels don't look disproportionately small. I'd guess that for a 45L a 3" lapel will look really small (kind of like the way the lapels on Mad Men look on Don Draper), so wearing a 3.5" tie with such narrow lapels would be a little off.
7/2/12 at 2:29pm