we lost alot at first. then i printed a thin, black grid on clear vinyl & applied it to the feed table. if we take the time to line it up right from the start, we might get a slight skew over long runs. if mister 'just-stuff-it-in-there! hurry up!' runs the machine, total loss! i don't know why the manufacturers don't put lines there to start with.
also, i found once it starts drawing material in, hold your vinyl roll down lower than the feed table & pull back a tiny bit to put some tension on it. less wrinkles. good luck!