I used to have one of these in 6x6 mode. I assume you have a carrier - I don't see one in the picture. It is a long time since I had it (we are talking decades), but I would start with flat side down for single condensers, and curved sides together for pairs. I think my 6x6 model had the condensers mounted in a cylinder that fits inside the lamp house. I only remember having one set.
The head tilts back to get the carrier in. I think it is best to set the negative in the carrier, then insert it rather than take the weight off and slide the negative strip. But that was with the 6x6 glassless carrier.
The parallelogram head mount works well, but you may find that you are moving your masking frame a lot. On the other hand, the head won't twist, which it used to do raising on the column for my less than pristine one.