I have a room dehumidifier rather than one for food, and it really helps. I put it near the items I want dried, then just direct the outflow of air (which is warm and very dry) over and past the gumpaste items. I’ll often use a cake board or cookie sheet propped up, or even just leave the upper oven door open (on my double oven), with the dehumidifier underneath. This is especially great for drying my wired roses as they hang nearby!

I have also, in an emergency, put the gumpaste item on a just-large-enough piece of wax paper or cardboard and set it on a cooling rack directly on the dehumidifier. BUT this is precarious, and I worry about drying the outside that quickly and whether the middle isn’t particularly dry…

If I need to dry my fondant decorations quickly, I place them on a parchment lined cookies sheet and put them in the oven and turn the oven light on and let them sit in there overnight and the next day they are hard enough to use or build upon. Try it, it really works!