I was able to postpone the cab construction by adding more details to the water tanks. So I added water hatches for the tanks from PVC and ABS plastics.
Another typical detail on such Budapest locos is the location of the water-sucker inside or in front of the smoke boy support. The model was scratch-built from brass.
Also typical is the diagonal pipe running to the top of the water tank. With such details, the water tanks are done as well. Now is no more hiding to get the cab attached.
Finally, I found some issues with my builders plate. Seems there are differences in scale somehow….