I'm not an expert, just a big drip. But I've learned that there are good methods and better methods, and the best methods and set ups are what work best for you with your kit. I started out with just a rig, got it fit, and learned to dive sidemount and wreck. When I wanted to step beyond the rec world and start learning Tec, I found that Tec instructors had many useful comments to help me improve my trim, tighten up my rig, and make many of the movements easier.
Things like sliding d-rings, floating o-rings and a loop bungee, mounting my SPG down the tank rather than blinkers. There probably wasn't anything WRONG with how I did things before, but I'm not so proud as I can't take some professional level critique.
I recently dove with Andy. We spent the better part of a morning working my rig over, and I'd have to say that the results were very useful. And there's still a couple things I want to do. I could have just blown him off when he started suggesting ways to modify my rig, but I was PAYING him to TEACH me, why would I reject good solid, highly experienced critique?
The point is that there isn't a sidemount police. Some people might not want to dive with you if your set up doesn't satisfy them, but you can have good buoyancy, half decent trim, and perform all the critical sidemount skills and slip thru wrecks without constantly tweaking your kit and pulling it apart and redoing it. But what are you going to learn about how well it really works if you don't try anything different?