Man, Lucas has a good marketing team, since they got you hooked sinker and all
Which oil is best, i really don't know, im a cheap ass who likes marine oil since its about 10$ a gallon. Ive never had a engine blow up on me that was caused by lack of lubrication from the oil.
But, if the oil burns, it won't lubrate, main reason some brands have lower temp burns is so they can have better emissions and burns cleaner . But that can score up cylinder walls if it gets too hot (ie running too lean, or overstressing the motor) marine oil has a higher temp burn since the outboards are constantly held at wide open and will get hot.
So again, run what feels comfortable. As its better than nothing at all.