+1. Dynamic compression takes into account the cam profile (more specifically the intake valve timing).
Some light reading on the subject:
http://www.empirenet.com/pkelley2/DynamicCR.html
For something that's a daily driver or mildly used for towing, I'd use iron heads and compute your compression in the 8.5-9.0 range. Don't go crazy with compression if you are towing otherwise it will be more difficult to tune (ie: you may have to sacrifice timing). Don't forget you want a good torque band, and if it comes in low, that means you can cruise with it at lower RPMs even with a heavy load. You could probably use aluminum heads on a tow vehicle, but I personally wouldn't.