When fishing static dries flat calms my all time favourite (my all time fav fishing conditions as it happens) however don't be fooled into thinking this is the only time you can fish this style.
Light to moderate ripple all good stuff, but even in a Gale (good Highland drying breeze) static? (non-pulled, natural drift) dries can be deadly.
All the above excellent with this however be careful with the DHSedge as it can be heavily outscored if a specific pattern being targetted (Olives, or Midge best examples) when a more direct imitation called for.
As an all rounder the DHSedge is very good (you can simply substitute it for a shop bought Hog if you're stuck, which is another 'go-to' dry pattern for me, especially once the sedge makes it's full appearance) but not without it's limitations.
Failing the dries then short line two ginked bob flees (Hogs, Mini Muddler, Kate McL, Zulu etc) with an anchor pattern (Black Nymph, Silver Invicta, Connie Black etc) and aim for the margins. Short line style can also be excellent when wading by the way, and isn't restricted as a floating style.
If fishing dries and it is windy, for a wee bit variation, try and punch upwind and let your flies run back naturally as you would on a river
Hope this helps and have a good trip
Allan