Are you shooting a handgun or a rifle?
The stance I have depends on the pistol I'm shooting and which competition I'm in. For example, I'm not going to have an International Bullseye stance if I'm shooting at steel plates and moving through a course.
The weight I put on which foot also depends on if I'm shooting rimfire or centerfire.
Like everything, it takes time and patience to find where you're comfortable. The main thing is to have fun and continue your quest to blow up stuff!