My only real recommendation is mount them wherever it feels comfortable for you.
I've run a variety of flares (30 degrees to 12 depending on my mood) and i tweak them a lot in all cases. I run SRAM rival for what it's worth. I aim for as flat a surface for my palms as possible, while still maintaining decent grip on the levers from my riding position on the drops.
If your flares are wide it will be a bit weird and may might want to play with the rotation on the bars as well as the lever position.
Knowing what bars you're running would help with advice but ultimately it's going to depend on how they feel to ride - everyone rides differently!