The main limit on the size right now is the ceiling-) The enlarger doesn't have enough room above the table it's on to fully extend. It's extremely stable. The manual claims about 160lbs for the whole unit and after hauling it up onto the table I believe them. I've been thinking about making a lower table for it but I'm not sure about working at the 2foot height it would need to be. Does anybody work sitting in a chair? I'd really like my workbench back so I need to build something to put the enlarger on but the low working height is bothering me.