One problem he will have with a bigger tank is moving it.  An empty 100 a couple guys can manhandle.  Bigger is going to take equipment.  As a side note:
If it has more than 5% don't lift by the ears.
Wrap a couple chains around it.  I've never pulled an ear out and don't intend to.
Legally there several hoops to jump through.  There should be placards and haz mat papers and training and on and on.  Find a DOT officer in a bad mood and you'll wish you never heard the word tank.