I believe that a good quality HDEO diesel oil such as Rotella, Delo, or Delvac would be awesome in you HD 96er.
The advantage to the big HD engines is that the oil ONLY circulates in the engine; no tranny or clutch to worry about. So the oil only has to concentrate on the engine. Sure, it's air cooled and not liquid cooled. But I don't think that the oil get's much hotter in the HD engine than a typical turbo-diesel truck, which sends the oil into the exhaust heated turbo bearings, while under a hard pull with a load such as a travel trailer. Seriously, a typical HD engine is no harder on oil than a turbo-diesel.
My friend has a couple of HD's; a Springer, and an Electra Glide Standard. He has oil temp gage dipsticks installed. His typical temp range while in motion on the the back roads is around 200-210 degF. Only while stopped for long periods in traffic does it rise; sometimes up to 240 degF or so. That's not outrageous.
I have tried, often unsuccessfully, to convince HD riders that a quality conventional HDEO is the way to go. Typically better oil than the HD brand, at a way better price.
And warranty (which is only 1 year, typically) shouldn't be an issue because they admit up front that HDEO is an acceptable alternative. Harley-Davidson oil is nothing special; in fact, it's quite ordinary, really. Look up some of the past VOA's.
HD thrives on brand loyality. In fact, they make as much money on merchandising (branded name sales such as shirts, hats, coffee mugs, clocks, playing cards, etc) as they do on bikes. The loyality to HD runs deep in many people. They will buy anything HD because they have been trained (or brainwashed, in my opinion) to believe that HD is simply the "best" of everything.
The choice is up to you. $10/quart for average oil, or $2.50 a quart for premium HDEO; which do you prefer? BTW - their oil filters are nothing special either, unless by special you mean "overpriced". Get a black or chrome Wix and be happy there, too.