Wow! First of all a Big THANK YOU for all of the quick and informed replies - that's what makes APUG the best place in the whole wide world!
To answer some of the loose ends: Yes it is a condenser enlarger and yes I adjust the condensers for each film format.
I have been getting the problem regardless of how far down I stop the lenses. I used to use the smallest aperture but then read that diffraction can occur at the smallest lens opening on the enlarger as well as the camera so last night I tried stopping down to the middle stops - still no edge sharpness (fuzziness no better, but no worse).
I use a 50mm lens for 35mm and a 75mm for medium formats. Again, the quality of these particular lenses is very suspect - for example the 50mm only has four, count 'm 4, aperture blades! I have only been enlarging to 8X10, printing the negs as full frame as the different ratios will allow.
Les seems to have the ultimate alignment solution, but since, to partially quote Paul Simon, "I am just a poor boy..." (and in fact I was once a boxer), I am leaning towards better enlarger optics since they won't really go to waste anyway. Based on the responses thus far that seems like the next step.
Thanks again, you're all the best!