…my setting would have a military composed of primarily aristocrats…

Those would be the officers, since I’m hazarding a guess that you’re envisioning dashing fancy uniforms; where do the rank and file come from? If you conscript commoners on a war-by-war basis, you need to wait until harvest season is over. If you have the food surplus to maintain a standing army, where do they come from? Is there a draft? Volunteers? Domestic or foreign mercenaries (which can be risky?)

(You cited Fantasy Russia as the source of your character’s outerwear; what kind of culture(s) and terrain(s) will he be living and adventuring in?)