Thanks for the replies everyone but the debate is over. For less than the cost of the Hollowgam crank itself I ended up buying an Ultegra R8000 52/36 crank, Dura Ace 9100 12-28 cassette, Dura Ace HG-901 chain, and the Wheels mfg BB30 adapters. As much as I wanted the Hollowgram, the Ultegra will look the part with the rest of my R8000/8050di2 setup and give me piece of mind as I ride. I think the combination of what I just ordered along with the soon to be released Ultegra R8050di2 front and rear derailleurs should be a nice shifting groupset.
One thing I don't understand is why Shimano makes a 12-28 cassette but not a 12-30? They have an 11-30 so why not 12-30 to help close the gap? I've been riding a 53/39 with a 12-28 and it covers 99% of my rides 99% of the time but there's one climb that gives me trouble (Sugarloaf mtn) so I wanted to lower my gearing just a bit. I'm hopeful that going from a 39 to a 36 small ring up front will do the trick. I almost got the 11-30 DA cassette but I know the 12-28 will feel better for the majority of rides I actually do most of the time.