You should support the candidate whose platform more closely aligns with your political leanings. If you are a conservative then the answer is clear. You should support Toomey.
If, on the other hand, your screen name on FR is Common Tater (or if you agree with his illogical logic), you should probably support the most liberal Damocrat (did I misspell that?) running.
I am not trying to be smart with you. Just getting a friendly jab in at CT.
Basically the essence of my thinking is this, if you agree with the candidate enough to vote for him you should support him financially.