Frahm tuning BELL 407

Iam playing around with tuning the frahm on a bell407 for a client. IT IS HIS WISH THAT THE FRAHM REMAINS INSTALLED AND HE CANNOT BE CONVINCED OTHERWISE.(ive tried for years) With that out of the way, do you have any tips for tuning it ?

Its a particularly dificult bird to T&B and get it to be comfortable in flight at the same time Just getting it nicely tracked and all within limits is easy but then it has a nasty 4/rev vibration that the client wants gone (vibrates like a washing machine going at mach fuck)[ after 30min flight the soles of my feet started going kinda numb]

Tracking it to smoothe out that nasty 4/rev is also doable and it can be really smooth in flight However that causes it to go way out of vib limits especially at 130kts >0.5ips even tho the overall ride is far far nicer.

Mechanically the helicopter is in a great condition as the client doesnt mind spending money on parts and mainteneance, we basically have an open check to replace whatever (especially if it can help with vibration) We are using the microvib 2 and i know for sure its all good as we use it on other aircraft we maintain and never have any issues

Any experienced input would be greatly apreciated