I wanted some opinions of darby's . Im not a plasterer by trade but ive done loads of plastering over the years and have 13 - 14 " trowel . I like the idea of a derby for the 1st hit on the plaster to get a nice flat base to work off rather than a trowel working it and creating mini-dips here and there. I have never seen a darby in action and just wanted some help as to whether its worth investing in 1? .