Does anyone have any experience making an adjustable (4 blade type) enlarging easel? I've looked on ebay and at the four blade offerings from B&H and Adorama and been blown away by the prices of 16x20 and larger ones. (I have 2 14x17 4blade easels...the second is a really excellent freebie thrown in by B&H with the LPL 4x5 enlarger in their current catalog). I need one for prints on 16x20 paper or larger. Help!!!