I like a). Given the option, I would try to max out the flowrate, and get a rad that can cope with quick water (a heatercore). You
should be able to bleed out most of the air from the loop, if not, run the loop with the case on its back, that should get most of the rest. I'm assuming all the lines and fittings are 1/2 inch ID, including the output on the pump (the barb might be too small for 1/2 inch tubing, I have 3/8 silicone on mine.). Then I would get a rad with a low pressure drop (heatcore, again).
The final touch would be to get 2 190cfm deltas for the rad.