Thank you for all of your responses. The Beseller 23C III as I am using it, is a dichro head, (not using it with its condenser head attachment) so I can just dial in the contrast I desire. I didn't install the condensers (is this correct?). The lens is new and free of fungus as is the bulb (new) which is an 85W halogen type.

In terms of vignetting, does it happen with wide open apertures? Would I avoid this problem stepping down a few f stops? I have a 105mm that I use for my 6x6 enlargement. Would using this lens change things? My 35mm negative is an outdoor sports scene of my son in a lacrosse game on a sunny day with trees in the background and turf in the foreground. Paper used Ilford MG FB glossy. Does 30 seconds sound too long for an adequate exposure for a 11x14 enlargement at 2.8?

Forgive my basic questions, as I picked this up late in life (never took high school photo), just doing it on my own.