Hello Dfoo,
I own an L1000. I, toot, bought it without the complete set of condensers. (when this machine was new, the condenser prices was awesome, so the photographer buyed only the one exactly needed).
I have found the missing condensers one by one on Ebay and on second hand shops dealing with pro equipment. So do not despair.
In the meantime I used the beast on 6x6 with Nikon lenses (80 and 105). In order to even the light output I played with the height adjustment of the set of condensers and centered the bulb as much as I could. I also tried to reverse the condensers (the curved face facing each other, but the one originally in the lower place now in the upper slot). Then I put a thick piece of glass on the filter drawer, this glass having one face frosted. This way, the size of the light bulb seen by the condenser is huge and you've a semi diffuse head with more even lighting. Another solution you may consider is to put a sheet of frosted glass between the second condenser and the negative stage. It will even out the lighting and make it a diffuse head. You can also try different enlarger lenses as the entrance pupil is/could be different and conjugate differently with you set of condenser.
Last but not least, you may find the cold light head (which is a box fitting inside the condenser box) but be aware that this one was devised before multi contrast paper was in widespread use and is far from ideal for them. As Aristo is quite out of business, they wont make a new tube for them (it has to be custom made as they never made the tube for Durst).
Feel free to contact me with precise questions if you wish.
Hope this helps.