I believe you're in the right track. IMO the best available full synth around is Delvac 1; the only drawback is its cost.
Since cost is very much an issue, what I have in mind is to create a concoction of Delvac 1 and another dino oil, preferably JASO DH-1 rated and a 15W-40 multigrade. I am looking at a ratio of 4.3 liters Delvac 1 plus 5 liters dino oil. This should produce a semi-synth that I plan to use only for 5K km or 6 months, whichever, comes earlier. Delvac MX dino oil is a candidate early on, but was dropped on account that it is not JASO DH-1 rated.
Assuming you're with me on this plan, which is the best dino oil currently in the market that should fit the purpose? Your insights on this would be much appreciated.