Just a reminder, the HexChat schemes are "temporary", only the palettes and their color order were imported, I don't have much time to play with them at the moment and HexChat seems to have 16 colors + background (please correct me if I'm wrong here) which makes mIRC hard to copy the same themes.
Not sure I modified anything else but Tempesta and Tempesta2 background is 2 points lower again, now 24,24,24 (identical to the Zenburn Darker themes), more readable this way.