I\'ve been playing some futsal myself, and think that what you need - besides good indoor shoes - is a kit that is light and \"breathing\", since the humidity and temperature is higher than when you play football outside. The idea of this kit is to have a light mesh\'ish fabric going from under the arms and armpits, down the side of the body, and continuing around the shirt and covering almost all of the back and the spine. In other words, the places where you sweat the most. I\'ve also done the same with the shorts, on the inner thighs and on the middle back.
The indoor pitch is a lot smaller, which makes the distance between the ref and the players shorter at all times, so I figured it would work with smaller numbers, as long as there\'s one on the front and one on the back. The player name is, as far as i know, just estethics, and not necessary for the ref, so I thought I\'d just put the initials on for a change.
One kit is with pinstripes on the front, one without.