if i was gonna be splittin hairs id say you actually need about 4 trowels for the entire process.... each one slightly more flexible than the first, the first being a flat, stiff, cement trowel, like a 14x4 ragni...
in actual fact, all you need to do is vary the pressure you apply to the trowel with each pass and use the same trowel..
its known as....
plastering... :RpS_sleep: