Re: thick or thin base gasket?
I have used the JuiceMotoParts Copper head and base gaskets for a while now and will say this...
On a stock angle fire grubee, using a thinner .016" base AND head gasket, and shaving the head a touch - it'll do some speed and great power.
i am also using .025" copper head and base gaskets in my fred engine and it its definitely improved.
Forgot to mention these are infinitely reusable. I've done several rebuilds on my grubee with the same set of copper gaskets. They SEAL VERY VERY WELL. If you torque the assembly evenly and correctly they do at least several hundred miles without any weeping or leaks.