Proof Mind is Fundamental and Matter Doesn't Exist

[Pizza]

That's right-- it may or may not be.  However, given that mind is all I really know, and given that all the science we've been talking about is known only through mind, I feel reasonably justified in pulling out Occam's Razor and eliminating what I see as the extra assumption.

You are going beyond arguing against physicalism and are arguing against realism.
You are exaggerating the simplicity of idealism and the complexity of realism. Assuming a world external to thoughts and experiences which is somewhat knowable through thoughts and experiences isn't really too much of an assumption. If that's "too much" all the worst for Occam's razor. Occam's Razor is a rule of thumb not the end all be all of inquiry and is moot for there is good reason for realism. Realism back up by strong intuitions about how objects behave when we aren't looking at or thinking about them. I don't think that's a knock down argument but it shows realism to be rational.

Subjective idealism is self defeating, because if all that is required for existence is being comprehended by a mind and my mind comprehends to some degree the idea of "something beyond conception" then things beyond conception exist.

However, given that mind is all I really know, and given that all the science we've been talking about is known only through mind,"

So what? Then the external world is somewhat knowable via our ideas and experiences. That doesn't refute realism at all, yet alone physicalism.