A couple of thoughts on this DDW stuff...
On our previous boat (the first real Insatiable) which was an IOR MkII one tonner with all the nasties that implies we did thousands of miles wing and wing with a poled out genoa. She did roll some, but sailed quickly and in good control. Another system we used in light condx was to set a second genoa, pole out the windward one, put two reefs
in the main to flatten it out and sheet it amidships as a roll dampener. This got nearly as much sail area up as our kite with much less work. We didn't have a furler, but did have a foil that allowed setting a second headsail easily. So Barnie, I can't agree that these sorts of setups are so bad as you say... worked well for us, anyhow!
Now on I-2, which is a more modern hull
shape, fractional rig w/ sweptback spreaders, we still often go wing and wing when sailing deep. Yes, the main isn't trimmed out all the way, but with a 120% gennie on the roller it works well indeed despite the theoretical faults. We've hit much higher speeds (best yet is 15.6 kts) than with the kite, because as Weyalan says, setting it in much breeze with only 2 on board is too scary for us. Interestingly, we also often use the poled out genoa as far up as ~100 deg apparent. Requires rolling a couple of rolls in to keep the shape, but it seems to be about as fast as conventional trimming, and in situations where the wind is oscillating a lot it saves lots of deck work.
And Jobi, do note that folks have used two jibs set on the forestay with sheets
run to the tiller as an effective self steering
setup when sailing quite deep. The Hiscocks were admirers of this practice.
We know that sailing near DDW is not the fastest way to get downwind, but sometimes external factors demand that course, and sometimes the extra effort involved in frequent gybing as one "tacks" downwind outweigh the greater VMG acheived.
Finally, until you have sailed a bunch of miles in your Hinterholler you won't know just what works best for her. Boats really are different in the way they behave at sea, and they don't always seem to follow theory.
Good luck with your sailing when spring arrives.
Jim and Ann S/v Insatiable II lying Gladstone Qld, Oz, en route
to Tassie again!