> Regardless, s-2 glass fiber is probably a better choice
I would appreciate if you can elaborate on that. Not being a material scientist, it's not obvious to me which option is a better choice here, but I am curious to learn.
Material "strength" is often misunderstood in popular science articles.
Spider dragline silk is notable for it's high strength for a stretchy material. These two properties are typically a trade-off. This means that it can absorb a lot of energy before breaking. Great for sutures, climbing ropes, stopping bullets.
For a pressure vessel you want high strength and you don't want it to stretch. So the unique property of spider silk is wasted in the application and it's outperformed by conventional non-stretchy fibers.
If you want a basic understanding, read up on and understand the difference between compressive and tensile yield and ultimate strength (and the specific variations that account for density), toughness, modulus of elasticity, and hardness.
I would appreciate if you can elaborate on that. Not being a material scientist, it's not obvious to me which option is a better choice here, but I am curious to learn.