That is cool! I have tons of 20x24" sheets and print them in a similar fashion. I pin them to the wall and rotate the enlarger sideways. Thankfully i have HUGE developing trays as well, i got them in the local trading post years back for $20. But its a pain and takes ages to print 1. Usually takes me about 20 minutes per print. The exposure is the most critical thing, because the enlarger is not really meant to enlarge to such a size i have to be careful not to bump it during exposure...man my darkroom gets messy with these prints.