I am having difficulty getting a picture that is really clear for you. This is the best I've got. I am sure other people's systems work but I like the Cooling Component's set up real well. It covers the entire radiator with the exception ov about 2" at the very bottom.
The secret to efficient cooling is getting cool outside air movement through every inch of the radiator surface possible. My car will sit and idle on the hottest day and the fan will cycle on and off. To go to my daughter's house I have to cross a mountain that is about a 6 mile 6% grade. I would not want to have to pull Monteagle on a 90 degree day but I scoot right over it without issue as long as I get to the mountain early in the day.
One other note. Flatheads hate retarded timing. The more advance you can run on your distributor without pinging the cooler you will run on a hot day. Since the exhaust ports run through the water jackets, the exhaust gas acts just like boiler tubes in a steam engine. The more combustion that is completed in the cylinder head the better. I mentioned earlier, I run a Chevy distributor which has all the vacuum advance the engine can stand.
I also run a S-10 five speed that keeps the rpm's down which helps. With a 3:25 rear end, I am probably turning less than 2000 rpm's at 75 mph in fifth gear.
Good luck with yours.
John