I use a board that has the grooves in the back, roll your paste out so it is long enough that you can use your cutter with the groove in the centre, insert a wire into the groove I use a 26 , then carefully ball the edges and vein.
I don't know what cutter you have, but there are excellent instructions for a sword fern found in Alan Dunn's "The Wedding Cake Decorator's Bible". I would imagine the same technique could be used with the cutter you have. This is what I use when I make ferns.
I hope this helps you. It is an awful feeling to have a cutter and not know how to properly use it!
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