Hi Gomari,
I am surely not an expert and probably this is arriving one week too late, but just in case it could help, I think Eric Fattah wrote a nice document about the frenzel technique (and his own improved version: useful anyway when you dive below 35.. or you do FRV or FRC) that you could download from
Liquivision F1 and Fluid Goggles Home I red it and found very useful.. after a while you feel you can master rather well many parts of your throat that you did not even know you had.. :-) well you probably already know how to, but just in case.. if you don't, be careful with packing... I nearly blowed me up.. =:-0
