hello and welcome.
i also buy trusted brands from trusted online sites. i wait until a good sale with little or no shipping. if i see something i like in a store, but i'm not familiar with the manufacturer, i wrap the fabric tight around my wedding ring. if a see a glimmer of gold, then it's too thin.
remember, though, when you wash fabric the weave does tighten up, so if a fabric is on the edge as far as thickness, prewashing usually solves that problem.