With the valve spring pressures of a stock inline six, 1000 ppm is more then enough to protect the cam and lifters. It's very likely you can get away with any oil you want. I have been running standard 10--30 in my 250 for years, going on 19000 miles now, but I have US made Rhoads lifters. The Rhoads are quality made but also bleed off at low rpm reducing the spring pressure even more.
Since the "oil issues " started back in '07 , I have yet to read where a stock engine has killed a camshaft or lifter that had been together for years. What you do read about is the new cams and off shore lifters, or the extreme lobe, thumper style cams going bad. Today it's off shore lifters, and no amount of additive or even luck, will keep them running.
