When using screws in a part, what is better? Thicker or thinner layers?

When using screws in a part, what is better? Thicker or thinner layers?

The screws im using are self tapping and seem to work ok until it gets over tightened, then it splits layers. All the material i can have between the hole and outer shell is 3 perimeters

I’ve tried that, but then i only have two perimeters of material around the hole

That’s what i tried. The piece that holds the screw isnt that thick so the bigger the hole is, the less material that can be around it. Its a peg