This list of 6 element lenses for 6x6 enlarging is not that long. Just keep searching ebay keh and the for-sale ads here and LF forum until one comes up at a reasonable price.
LIST(exact wording/spelling is important):
Nikkor 80mm f5.6
Schneider Componon (-/+ "S") 80mm f4 or f5.6
Rodenstock Rodagon 80mm f4 or f5.6
Fujinon EP or EX 80mm f 5.6
Koumaron S 75mm f5.6
Last year I replaced my Wallensak 50mm and 90mm with Fuji 50 and 80 mms. The only differnce I find is easy of focus as the Fuji 50mm is 2.8, and although the Fuji and Wallensak 80s are both rated at 5.6 the Fuji seems brighter. At working F stops of F 8 or 11, I find the Wallensaks to be just as sharp. I have not printed color in years, but I think the Fuji's will much better in color work. Kodak enlarging extars are also very good.