We'll have to open the question up to others that have experimented with it. The Slic3r INI files from MakerFarm had the first layer height at 0.35mm, and I just stuck with it. When I migrated to Cura/Cura Engine, I ended up configuring it to match the first layer settings I had been using in Slic3r. Simplify3D doesn't have a setting for an explicit first layer height, but it does have a percent adjustment you can apply to the first layer. I've left S3D at the default first layer height setting at 90% of my normal 0.20mm layer height.
I would imagine that within reason, slicers should be able to provide consistent first layer results across a range of first layer height/width settings by adjusting the extrusion flow and line spacing accordingly.