If you want, bounce the sun gun or flash it will give very soft natural shadows. Obviously the flash must be pointed at the ceiling.
pointing either light will give harsher shadows. For B&W increase the exposure a bit.
An 80B filter will correct Portra for use with your sun gun which is a 3400k source. You need to increase exposure by
1 1/2 - 2 stops.
Movie lights were made to be used with Kodachrome Type A film, which was balanced for 3400k.
For exposure with mixed complexions use an incident light meter or with a reflected meter, read the palm of your hand
and open the lens by one stop. This should be a starting point and depending on results can be modified up or down.