controlling phase of mc.phasor
Using a mc.phasor with several voices, I would like to control the phase of each channel independantly. I can do this by sending a "setvalue $1 phaseoffset $2"message. Works nicely, but change is very abrupt and generates clicks. Right inlet doesn't accept line~ signal. So I just can't figure out how to achieve a smooth transition between two phase angles. Any help?

If the phases need to be set only once then I would stay with your current approach.
If it is meant to be changed in real time, I see two possible approaches:
Use [mc.sig~] to generate a signal for all of your phase offsets, plug its output and the [mc.phasor~] output into the left inlet of a [mc.%~ 1.]. The phasor and sig signals will be summed and wrapped back to the 0. - 1. range
right inlet can receive a signal that will reset the phase at zero-to-non-zero transition (see last tab of the [phasor~] help file). I think that with a bit of logic you could make use of that to offset the phases of your [mc.phasor~] to your liking.
I'm a beginner in signal domain, so all this is to be taken with a grain of salt as they are just assumptions without actual testing.