My understanding is that the most commonly used metal stud sizes are 1 5/8", 2 1/2", 3 5/8", 4", and 6". I've inherited a project from an employee who is no longer here, which has been designed with 3 1/2" and 5 1/2" studs and I don't see why. I see from a Google search that those sizes ARE available but maybe not as easy to find. Is it better to stick with the sizes I listed first?