But I am curious why you say you would be reluctant to train with Gleason Sensei without a tsuba. Do you think he would hurt your hands accidentally or intentionally? Or would you be worried that you would accidentally hurt your own hands? Or are you simply pointing out that Gleason Sensei does a lot of techniques that require a tsuba?
He does use a number of techniques that require a tsuba.
But mostly it's because he tends to push students right to the edge of what they can deal with -- in empty hand practice as well -- and a tsuba gives that extra bit of protection against one's own mistakes.