My preferred setup involves frozen filets (thawed) with skin-on, but that’s only if lucky around here. With skin still on, I do them right on the grate, indirect. If the skin comes up with the fish or stays on the grate it’s no matter; we don’t eat it anyway.
If they are packaged as skinless, they cook the same way but can be harder to remove from the grate without tearing. Planking works fine in both situations. I look for wild caught, not farm raised. Seasonings can be basic S&P, or all sorts of things.