previous banded tournies typically have a high and low rating range.
all the higher rating ranges have a very small number of entrants.
the solution may be that the higher ranges also allow lower rated players to enter. why not try having only a maximum rating and no rating minimum .... only the low rated players keen to get ground into the dirt by the pros will experience that joy ... the other low raters will play each other in the "sandpit".
i am not at all sure how many will enter, but it might be worth a try.