Do what your brain tells you, it's your equipment and your burden either way. Sounds like you have heavy value in playing the manu's playbook, that is a sound strategy. We have guys running heavier then 30 weight with no mds issues. If you believe in poll stats around 40-50% of the forum uses 30 weight. Which means your strategy is in the popular side of it.
However, the entire reason this thread became a "thing" is because of hemi tick and cam/lifter problems and issues. Ask yourself the question, did fca recommend 5w20 for hemi's because that is what they wanted, or what the epa wanted? If you believe it is what FCA wanted, then why the hell did they ask for 40 weight in the same engine non mds in the HD units? Because that is how you protect metal is the answer, and the epa isn't up their ass on HD units. Not only that, but the api forces oil formulations to be sparce to get their ratings in 20 and 30 weight oil, why would that be?? They have no such requirement on 40 weight oils. FCA sold you a truck, now it's yours, just like ours are ours.
There is a lot of misinformation in this thread, a lot of us have learned as we go, a lot of info has changed. You don't need to read the thread, but there a group of guys who have had hemi tick go away and have recorded their experience, and that is the value here. h395 has done the most work on it, as in testing the most oils over time with uoa's, U&A as well killed his tick, and RLK has some great info backed up in uoa's and has ideas on how best to protect his cam, dude spent his life jetting around the world working on helicopters and has done great work here. Whether or not the work we have done will actually gain us Cam/Lifter life will never be known as a fact, but what we do is make a strategy based on science and roll with it. Cam/lifters are a weakness in these hemi's even if you don't have hemi tick. Just maybe providing those items with a hearty oil both in film strength and detergency will allow them to live longer. FCA made a hemi specific oil 0w40 PUP in tandem with Pennzoil that is similar in strategy to what we've been doing here before that oil was even made. So I would say we were on the right track. These fellas contribute not only on oil, but these guys have many many dyi threads. I'm about to use h395's dyi thread to do my first coolant flush, so I got to get at it or this day will pass. Peace Burla
Sorry about not just posting three guys, there are many many more valuable contributors, I mean no disrespect. It is just those three have been here almost since the beginning and as all of us know have really went through trials of finding lubrication strategies. Welcome to ramily if don't mind my say so as you still appear to be new here. Best source for Rams anywhere this side of tdr for Cummins. If I had another Cummins I would be in both forums, but for hemi guys this spot is it imo.