Dumping the scoop and wheel clerance are the main concerns. The 24 and 30 seem to hold the same amount of dirt but the 24 must be raised higher to dump. Also the 30 makes a fair tool for leveling the dirt. I bought the 24 and have problems dumping it but have no problems with my brothers 30. But t the 30 will hang my tires. Check the length or the scoop to see if you can raise it high enought to dump.