Sized bows are only necessary with a wing collared shirt where the buckle on an adjustable tie would be visible. If you are planning to wear a wing, better to have a sized bow, even through it doesn't match.
Or you could call Charvet in Paris and telephone order a sized satin bow. They stocked them last time I looked.
You can be comfortable in much heavier trousers than jackets and over time I have moved to pants that weigh more than my odd jackets as they drape better.13 ounce gabardine, for example, is fine in all but the hottest weather. 16 ounce flannel is good up to 65 degrees. Etc.