Not at all in Deflemask... no controls for it, though it is in the core programming to support it. Would be nice.
You can use the multipliers to change the octal range of each operator separately from each other, and get almost total pitch control for each one. Although it takes a bit of tinkering and a workaround.
Algo 7 is the nicest I've found for chords, and pseudo saw chords when you bump the Feedback up to 6 or 7. Using the AMS creates an interesting ambience as well for fading chords in and out.
Yeah, using FM Drive VST or programming in assembly yourself is the only way to get real total control for Special Mode. I still enjoy what can be done with VGMM, though.
Also... you can get major sine chords with any FM channel... chords of 3. Check out this recording from Deflemask:
https://drive.google.com/open?id=0B2C16041iMhgMVE4VUNyNHd5TjQ
The sine chords are coming out of Channel 1. I analyzed Tim Follin's Time Trax, and found that he was changing the multipliers for sine chords for a single channel, multiple times within the song on the same note, I believe. That guy was going crazy! :)
So there's so many cool tricks with this sound chip.