[quote user="mitsdude"]
So, looks like you wait and print a batch of decals at once or pretty much waste most of a sheet to print one decal.
/quote]
You can print one decal or a whole sheet, or anything in between.
If you keep the 'feed' end of your sheet intact, you can run the sheet through any number of times---just make sure your print area corresponds to a part of the sheet where there is still a white/blank region left. If you know you're going to reuse the decal paper sheet, print out your first images at the bottom, and move up as you go; that will leave the printer a larger, stable area to grab when it starts feeding.
You can also run a 'test' print on a regular sheet of paper, then cut a bit of decal paper that matches and tape it lightly to the sheet, then run it through again to make your decal. (If it's a large image, I'll print the test sheet on 'draft' setting to save ink. Just make sure to reset it before you run the actual decal.)