That's kind of what I was hinting at.
He could run out the OCI's to a much longer interval, and run the 5W-40 Duron. Or, run a 5000km OCI, and run whatever inexpensive farm/fleet HDEO he can find; at that low a mileage, any HDEO would hold up, and still have life left when dumped.
Again, "best" is the most pro's with the least con's. And "best" is different for nearly every person in a different situation. To me, the whole question of what's "best" is moot. The "best" advice we can give is to offer choices for certain scenarios, and let the OP pick which "best' fits his needs.
In my opinion, short OCI's + synthetic lubricants = wasted money! So a synthetic is NOT the best choice if you're going to OCI frequently. It's not cost effective. There are hundreds of UOA's here to show that good quality group II oils work fine.
Stretch out the OCI and the whole concept of "time is money" starts to make sense. It can be very effective to run premium lubes and filtration to long OCI's, especially if you're on the road a great deal. For some people, down time is expensive, perhaps resources are limited, and synthetics and BP filters make good fiscal sense.
Bottom line: beauty is in the eye of the beholder.