Great article by the way for more info.
Toyota Supra MKIV : Powercruise Taupo 2009
Yeah it's for a Supra, but the concept is absolutely the same. Key thing to note is how the temperature affects the length needed.
120hz @ 20c (68f) length needed is 710mm (28")
120hz @ 80c (176f) length needed is 780mm (30.7")