Most performance show participants use dolls these days. That means that having a fixed fender would prevent "action" in the saddle. Probably not an issue in some classes, but for gaming it's a must! I hang my fenders on sturdy pins mounted on the lower skirt, providing a free swinging fender that still adjusts, and can take some pressure from the rider. It's critical that the fenders are perfect mirrors of each other and mounted in a way that provides symmetry.
Symmetry. One of my favorite words having a tad of OCD. Nothing is more important in a saddle's structure. It's a chain reaction if one piece is out of place. When the pommel is crooked, that makes the seat crooked, which makes the upper skirt crooked, etc. Imagine spending countless hours tooling something and then having it look sloppy when put together! It's a slippery slope that can ruin all your hard work, so it's important to take the time and assemble it symmetrically.
I make marks on the upper skirt before assembling it to make sure both my rear conchos are symmetrical. A hint: It's a lot harder to make accurate measurements when it's already being put together. Make sure that the horn is centered on the gullet, and the rear cinch is mounted symmetrically, and your saddle will look neat and clean!