It is my unproven contention that the inlet area was already oversized but too much back pressure on the cooler required more exposure air.

To answer this, I'd really need to do the ASI test, and eventually I might.  As you may recall though, I only recently closed the cowl cheeks permanently.  Before, I had the bulkheads loose, so I could put them in, or take them out to test the effect.  Leaving the cheeks open allowed a large amount of air to exit in addition to the lower cowl outlet.  It was amazing in fact to feel how warm the left side of the fuselage got due to the hot air coming the exhaust side of the cowling.  I used to joke that I could use it as a heater.  At one point, I even tied some strings along the exit to see how much airflow there seemed to be in flight.  The point of this rambling is to note that removing the cowl cheek baffles had almost no measurable effect on the temps.  From that, I concluded that more exit area wasn't what I needed.  

Another motivation for increasing the oil scoop size was to try to even up the water and oil temps, for a given outlet size.  At the moment, I have enough (if not too much) water cooling, and not enough oil cooling.  If I can get to the point where I also have enough oil cooling, then I can control both oil and water equally with a cowl flap.   I'm not entirely ruling out the possibility of a supercharger, so for the moment, more cooling is better.   

Consider also that my goals are different from most.  I don't consider the RV-3 to be the ideal cross country plane (single place, no panel space, less fuel, baggage area, etc).  It's really more of a toy to me.  If I can cruise at 200 mph, at a reasonable altitude, regardless of fuel burn, I'll be happy.  This isn't such a lofty goal for an RV-3 with as much power as I have.  I'm more than willing to give up top end cruise speed to gain climb performance.  Without overheating, I intend to be able to takeoff on the hottest day of the Summer, and climb at best climb rate until I pass out from lack of oxygen.  Ideally, that climb rate will be close to 3000 fpm, and I'll stop just short of passing out :-)

One other final bit of rambling- there are lots of things that are not optimum about my RV-3.  Much of this goes back to the original builder, and there just isn't anything I can do to make it the way I want it.  I can live with it as a "test mule" for the engine, but I don't see me flying the RV-3 for more than another year or so.  I just brought the Kolb SS home, and should be able to get it back in the air by the first of next Summer.  This was another case where I inherited someone else's work, and much time will be spent un-doing the things I don't like.   At that point, I'm probably going to start a new (as in NOT some else's problems) plane.  The front runner at the moment is the RV-7.  Once the new plane is well under way, I'll sell the RV-3, minus engine, instruments, etc, and install those in the new plane.  

Sorry if that was more than anyone wanted to know :-)