I can assure you with total, absolute certainty that the Dmax engine could not possible care less what's in the crankcase, as long as it's a properly spec'd lube. Brand and grade mean absolutely zilch to this engine series. None. Zip. Nada.
If you intend to stick to one or two year OCIs, based on the miles you drive, there is no reason to use anything but a conventional 10w-30 or 15w-40. Either grade will provide excellent wear control and save you a ton of cash. I routinely ran 3 year OCIs out to 12k miles, on dino 10w-30 and had nothing but great results, even when hauling my RV out to the Rockies and back, multiple times. Honestly you can follow the IOLM in a Dmax and just use dino oil. Unless you suspect a contamination issue, UOAs are pretty much worthless on a Dmax; they've never showed an issue in a healthy engine, and the only proof they provide is that these engines are completely and utterly immune to brand/grade oil choices. It would be impossible for me to overstate this fact; 6.6L Dmax engines are some of the best wearing light-duty diesel engines out there, and they simply do not show any preference whatsoever to any brand/grade of oil, regardless of what your emotions thinks are important.
Probably the best thing going for your generation of Dmax is that there exists a fuel injection nozzle downstream of the cylinders, in the exhaust, for the DPF purpose. This means no fuel dilution that's otherwise common in other compliant diesel engines. (this is presuming you're stock). No need to worry about cylinder's washing down with excess fuel. I wish all the other diesel engines had this strategy; worth the extra expense in OEM design if you ask me.
If you intend to GREATLY increase the miles you drive annually, or spread the duration out over many years, then the syn might make sense. This would be smart only if you monitor with UOAs.
I have over 550 Dmax 6.6L UOAs in my database. I do statistical process quality control for a living. I would know if these engines had an oil preference. Trust me; they don't.