Some things may not transfer-over in the conversion, as they have no 'known' or 'managed' conversions. You will gain every possible shader value, for control, including areas which the textures/materials may not even use. The '!Iray Uber Base' can be used on every texture, but it does have a high rendering-tax, as it is kind-of a non-specific 'catch-all' shader that just turns everything on and used a 'close enough' conversion process to do the conversion. Increasing the light, will make it act like an HDR, as the lighting will cast onto the scene, based on the colors from the image, as does an HDR environment. Just be suer to set the color temprature to something neutral like 7200-7800.

It will make the sky itself become a textured light, if you place the texture in the emissive light color area. You can just select the skydome texture and apply the 'Emissive' shader to it, or the '!Iray Uber Base', and turn on emissive value. If you want the non-iray skydome environment to look good, and act like an HDR, in a way.

Iray daz3d