Refuting the Impeccable Logic of Calvinism

In many ways, the Calvinist theology of Grace is the result of a logical rigor which, despite feeling so very wrong, is (almost) entirely internally consistent. I understand this theology to be thus:

1. As a result of the Fall, Man is totally depraved.
2. Double predestination is in full effect: God actively decides who goes to Heaven and who goes to Hell.
3. If you are numbered in the Elect, it is through no merit of your own (see #1), but due to God's gratuitous Grace.
4. If you are condemned to Hell, you deserve it (see #1).
5. Christ's Atonement was only partial (see #2).

Additionally:
a) God can do no wrong, as he is by definition the Good.
b) God is omnipotent.
c) God is omnibenevolent.

If you admit a, b, and c, points 1-5 seem to be internally consistent. But internal consistency does not mean the system is correct. Calvin's theology of Grace, like so many others, is very much the product of a priori axioms. Even given the axioms a, b, and c, one can easily arrive at a very different theology of Grace.

For me, Calvinism poses two main problems: 1) God is unable to do wrong and, in effect, is not held to any ethical standard and, 2) Christ's sacrifice and suffering was only partially effective.

The tautology of God's righteousness defies the conception of God as "Good" in any sense that we can relate to. One asks Calvin, "Why is God's predestination of some to Hell just?" He answers, "Because he is God." This is not a real reason. God's standard of behavior may be different than ours, but if the meaning of "Good" is to retain any stability, the standards must be commensurate to our different roles and persons.

Regarding Christ's sacrifice, if it was only partial, does that mean that it was a mistake? Does it mean that God could not perform a truly efficacious sacrifice? If God had the choice (see #2 and b) between a sacrifice of full atonement and limited atonement, why (if c) would he choose the latter?

Even if internally consistent, Calvinist Grace corresponds poorly to both Scripture and to any well-adjusted person's common sense. It seems to be more of a product of a masochistic mind than a well-rounded construct.