U will need field barrier for the sp part but if you just want to float you wont need it. The only place I have found to be able to float at it at the ancient factory where the four robot alarms by the save point and recovery machine are. First you need to find one or where the two are kill one. The bumps on the floor that also go up the wall is where you need to be. First, find which one of the spots you want to be at next you want to position your self against the wall by the bump but not on it also have your back facing the bump and the wall then make sure that you are on the opposite side of where the robots are summoned by the alarm bots because they have to charge at u. Once hit you will notice that you are pushed back a little and you will be pushed back only a little at a time so it will take about 3-4 robots to do this fight or flee from them your choice. At first you will float a little so don't move after one more you will float high enough to where the robots can't hit you then you activate your barrier or just float but if you want sp I recommend that you have field barrier 3 and have about 800-999 mp so you can just leave your character there. If you want to get off just move or attack the robot in front of u.
Tip: If you don't have lvl 3 barrier or low mp I suggest buying lots of magical medicne.