The big mirror box is so efficient that I can get perfectly even illumination with an Apo Nikkor 240/9 stopped down to f/16. But whenever possible, I prefer working with a 305 or 360 when full sized 8x10 is being enlarged. That's with the CLS301 colorhead, not the earlier CLS300 which could only deliver ideal illumination up to 5X7 format size.
It appears that a long time excellent source for Durst enlarger components and special fabrication, Glenn Evans at Glennview.com, is just about to finally throw in the towel and retire. So if anyone needs something from him, they should do so promptly.