I shoot a 4" 686 that I made into a 40 S&W for IDPA. It has front and rear fiber optics, 6 lb. DA pull, bobbed hammer, cut for moonclips and chamfered chambers. There is only revolver class now, as most are shooting auto, there aren't enough revo shooters left to break it down further.

On any gun, the quality of the sights, trigger, and barrel are the main things that help you shoot well.

#1-yes.

#2-yes. Go easy, you don't need 6 funnels, just a small chamfer does the job.

#3-I find the fiber optics are helpful in all light conditions besides dark. In the dark you are using a flashlight anyway and the sights are silhouetted against the lighted target. Even black sights work then, as they all look black.

#4-I use a fiber optic rear with a deep notch. Deep is better than wide because you can still get on target quickly and still make longer shots accurately. The fiber front and rear together helps keep track of the front and rear relation to each other on the first shot from draw and during recoil between shots. I use an orange fiber on the front and green on the rear.