I think that enlarger takes SIXPLA, SIXTUB and SIXTIF lens boards that came with threads in both the sizes mentioned above ( 39mm and 25mm). So there are 6 lens supports that work on that enlarger.

So, use the SIXPLA for an 80mm lens, use the recessed SIXTUB for a 50mm lens and use the very recessed SIXTIF for a 30mm lens.