Hi Deb,
Hot Potatoes scores are always percents, i.e. the highest score is always 100, so there is no need for a separate "Highest" setting on the settings page.
If you set the "Grade weighting" for the HotPot activity to 100%, then you will get the behavior that you want, that is to say the percent score from the HotPot exercise will be transferred as it is to the Moodle grade-book.
Of course, once the HotPot score is in the grade-book, you can adjust its contribution to the course grade using the various weightings, averages and categories that the grade-book offers.
regards
Gordon