Gearhead,
No flame intended here... but I think you'd best do some more reading. Anastrozole and letrozole both work by the same mechanism. The only difference is that letrozole has a much higher affinity for the aromatase than does anastrozole.
As for your comment about using nolva while on tren... pointless. Tamoxifen is a competitive inhibitor at the ER. It has no effect on the PR. Either way it doesn't matter. Tren binds to the PR as an antagonist (just like winny does). Though it does bind to the PR as an antagonist, you don't see people using it to combat gyno from nandrolone or drol because it's affinity is so poor. Even if it did cause gene expression, it's affinity for the PR is so poor it wouldn't post much of a problem umless the dosage were very high.
Lastly... you're correct about the clomid. It functions as a mild estrogen antagonist (for the most part)... and it would have a small effect on water retention. It's not terribly effective though.
GetBig,
Aromasin (exemestane) is great if you can afford it. It binds irreversibly with the aromatase... which means that for it's lifetime, that enzyme isn't gonna do shit. You can drop estrogen levels considerably.
If you're lookin to ward off water retention while on a real heavy test/dbol cycle... then runnin aromasin and a low dose of arimidex concurrently will work wonders. Great stuff.