We found no limit to the amount of regular sacks you can insert into the goals but there is a limit to the amount of bonus sacks(4), we’re up to about 2,000 reg. on each goal
Edit: the pictures in this website (https://vexforum.com/wiki/index.php/Sack_Attack) and the app are different. The bonus goals are switched, unless you can turn the bonus goal (I haven’t read the manual), but I don’t think you can