I like to use StaFlo also, and yes if you don't wait for the starch to 'set' you'll get flakes. I lilke to spray the starch on damp fabric, it seems to absorb it faster. Distilled water is best, if you mix it with tap water, you should dispose of the unused portion after you're done for the day; if not, it'll grow mold, which is almost impossible to totally get out of your spray bottle. Guess how I found that out....As far as cleanning your iron goes , use a wet towel, hot iron, and iron the towel changing to a clean area as needed untill the iron is clean.
I only starch on a small ironing board w/ a cotton covering. You could use a towel w/ muslin cover to starch, easy clean up.