Thanks for the reply.
Maximum height for the trolly is 60cm because of the bathroomdoor wich is 2m high. That is why I'm considering to not use the top of the trolly as a baseboard, but only for mounting the enlarger. And then make an height adjustable baseboard on top of that so I can stand when I'm working with smaller prints.
80 cm wide and 60cm deep baseboard/trolly was my plan. I can increase the width to 90 or 100 without problem, but the depth is 60cm because of the size of the wooden plate. The width of the bathroom door is 73cm, so it's possible to make the trolly deeper, but then the top plate will be in two pieces.
"Drop wings" is a great idea, it will definitely be possible to make if I need more space.
My plan was to make a storage room in the trolly with shelf or drawer just below the top plate and then a room for adding weight at the bottom plate if it's needed.
I don't know how much mass the trolly itself will have yet, but I guess around 20kg or more, hope it won't be too top heavy.
I guess I should try to find some kind of steel to support the "wall mount" and make it stiffer so it won't flex.