Awesome model/scene Flak,.. bet that took some time.  We may have to wait for 6.1 update to get a decent HDRI setup in Bryce. I think the IBL is locked at a 90 degree angle and you would have to rotate the entire scene to get the light showing from another angle. I don't know if Bryce can use muti-layered/exsposures HDRI yet either. I always use the quality at 1 to speed the renders. Some Bryce IBL takes days to a week to render at a high quality on some systems.