I've just acquired my dream small format enlarger, a Leitz V35, in pristine condition, save for the fact that it uses the old 6604 bulbs. I've tracked down an adapter, and at the same time, am wondering if searching out a new-style mixing box would be worth the effort? Supposedly the newer 2-condenser boxes yielded much more even illumination, but it seems unlikely to me that the difference would be so striking that Leitz would have released the 1-condenser model in the first place. They seem more perfection-driven than that. So here it is: does anyone have experience with both the old- and new-type mixing boxes that can speak to their comparative evenness?