[orangustang]

I wonder if you would be able to achieve better efficiency by leaving the second exhaust valve functional, like the first stage on the 3-stage VTEC engines. If I had a SOHC rocker-arm setup like yours, I would think it worthwhile to play around with disabling one intake valve, then one exhaust valve, then one of each, and see which works best. They all seem like they would have their advantages, but I'm not sure which one seems the most advantageous.

2 intake, 1 exhaust = increased EGR effect from decreased exhaust flow, but higher VE from better intake flow
1 intake, 2 exhaust = lets less air into the engine for reduced consumption, but removes some exhaust restriction for better performance
1 intake, 1 exhaust = less total flow, still balanced like the 4-valve. Definitely way less power with the 4-valve lift, as you've seen.

I'm not sure which of these would result in the best fuel economy. As I said, there's some reasoning to support each concept, and it probably depends on your driving style.