I find the High Dynamic Range sliders to very useful and use them after adjusting exposure and WB. I'm surprised you don't play with them.
It would interesting to see a step-by-step workflow of other photographers using C1.
It's my understanding that the HDR sliders are infrequently used; reserved mostly for difficult images with very challenging contrast issues. I've not had any burning reason to experiment with them at this point.
Anyway, my current workflow is pretty much as follows. (Bear in mind that at this point I only really use C1 to decode RAW and set WB & B&W points. I then export to LR for all the rest
1. I set WB (I have no confusion about how to do that).
2. Then I work on W&B points. I bring in the bottom sliders underneath the levels histogram to the point where there is only a very slight hint of clipping (clip warning is on).
3. As with levels adjustments in Adobe apps., I rarely have need to adjust the output sliders - the ones on top in C1, the ones on bottom of Adobe Apps. But, since PhaseOne reportedly uses a different algorithm for it's output level adjustments (said to minimize harsh, highlight transitions) I dutifully set my outputs a bit inward as they suggest - about 4 and 248-250.
4. I don't adjust exposure or make any other such adjustments in C1.
5. I export the file (which becomes a tiff) to LR and refine from there.
I guess my main reason for starting this thread was to determine if anyone - especially Michael - uses the exposure slider in C1 to adjust the high end of the histogram (WP) before going to LR for further processing.