Hello.
Few years back I've been using awesome script for Vray, which automatically binds sun position to te most bright pixel (sun, usually) on the environment dome.
Now, when Corona added nice caustics solver, this would be awesome timesaver if you are using Corona Sun as the only light generating caustics.
I believe this is an typical scenario. It's even mentioned in official Corona caustics overview video.
Script is here:
http://www.scriptspot.com/3ds-max/scripts/find-and-bind-vray-hdri-sun
