I have Durst 600 and no plans to upgrade the enlarge. So, I am thinking to contact print 6x9(Agfa record) or 6x12(I do not have any camera yet in this format) like in the attached drawing. May I know is there any mask available to acheive something with accurate spacing and so on? My skills are rather limited to go DIY way... I am planning to put them on 18x24cm paper.