1. you have to set parameter H to LED off
= User defined, otherwise your "user defined" swashplate geometry that you adjust in the software will be inactive.
2. The swashplate mixing angle
will be the same as usual, that doesn't have anything to do with your multiblade head. So as your 450 has 120°
swashplate, set it to 120°.
3. The phasing angle i cannot tell you, this is up to you to find out: Rotate the head until one rotorblade is placed parallel to the tail boom. Now when moving elevator this blade mustn't move. If it does, increase or decrease the phasing angle.
4. RevoMix. Again this is up to you to find out how much is necessary for your application. In general Revomix shall support the tail gyro when the rotor load is changing abruptly. So if your head is turing counterclockwise the nose of the heli would go away to the left when you raise pitch, the tail would go right. So RevoMix has to counterreact with a tail control input to the left to keep the tail on track.
For the beginning I'd recommend to not use any revomix at all. This is considered as fine tuning and you first should try to get the heli flying before making such advanced adjustments.