Struggling with highlight rolloff when creating Ultra HDR edits of my photos

First, in case you don't know what Ultra HDR is, have a look at Greg Benz's page on the subject. If your phone/computer/browser supports HDR and HDR is currently enabled, you will see a stark difference between the left and right sides of the sample gallery.

I'm trying to make HDR edits of my photos, but I'm struggling to get colors to look the way I want them to. I find Lightroom's "Preview for SDR display" conversion to be significantly inferior to the normal SDR-only workflow, particularly in terms of highlight rolloff. For example, bright orange sunsets go from orange to yellow to white with harsh transitions instead of smoothly desaturating from orange to white as expected.

I'm wondering:

1. Is anyone else using this technology in any capacity?
2. Do you have any good tutorials on how to do color management in an HDR workflow?