You want NINE bottles (three nests of three). You can get the book on the routine at www.stevensmagic.com
look for Multiplying Martinis.
Harries makes an excellent set. Do NOT buy the 8 set from India.
The Rings N Things (older) version is good too, but hard to find and bring $$$$$.
The bottles Ken sold were dark green with plastic tubes (2). They had a lip on the inner top edge that made them easier to un-nest -- but I have used different versions (Harries and RnT) wihtout any trouble.
Again, thanks for asking... I'll probably to the routine in May at the Karmien convention in Portland area.