I have sucessfully emulated the Apple IIE text mode and I have coded the GR and HGR. This was the easy part. I am pretty sure Woz did not design the DHGR mode. I believe the Devil had a big hand in it's development. What I wanted to do was add a monochrome mode where I could get 560x192 mode to emulate a monochrome monitor. I also wanted close to the true individual dot color. On the Apple IIE emulator, when you write a 85 into location 8192, it displays differently depending on which monitor you setup. On a monochrome monitor, it appears as 4 monochrome dots. But on a color monitor, it appers as a solid gray line. This conforms to the way it is displayed on a composite monitor. Also, it conforms to Tech Note #3. But this tech note was written before high resolution VGA monitors were on everyones desk.
When I had my Apple IIE, I had added an analog RGB monitor, seems like it was a Sony, and used the RGB option of the AE RAMWORKS card. I do not remember what would happen in DHGR mode. I do remember having to wire my own cable. I guess it does not matter. There is not much software that I will use that uses DHGR. And if it does, it will probably be Tech Note #3 compliant.