Are there any hard and fast rules about wearing a black sporran with a brown belt or vice-versa?

I know Americans still seem to have an aversion to wearing clashing colors (at least I do) when it comes to the tartan and shirt/hose/shoes. Not so much in Europe. But what about the accessories. All I own are black belts with silver buckles. My sporran belt is black with silver chain and the two sets of belt hangers for it are black leather with silver snaps.

Should I invest in a brown kilt belt with brass or gold buckle?

The main reason I ask is that I'm making a sporran based on a pattern I got here. It's the one from 1750-80. It's going to be slightly larger and I'm tooling Celtic knots on the upper flap and front. I had planned on coloring it a saddle brown or maybe a mix of browns to make it look antiqued.

Keith