Personally I use a mostly control build, with some of the primary stat for the class melded where I can. I don't use any Brand of X abilities so I want to avoid unstable as much as possible.
I don't swap my setup around for different synths as I find this flexible enough for any difficulty.
Skill setup
Master's Mend
Byregot's Blessing
Perfection
Culmination
Comfort Zone
I use MM straight away, then spam careful. First time I see rainbow orb when my dura less than 100, pop BB and Per then careful for ~150 quality. This leaves 2 turns left on BB. If either are red/rainbow I'll use Culmination and careful for another 100+ quality. If both turns are white/yellow I will save Cul for later in the synth.
Depending on difficulty of synth you can use CZ with standard for alot of progress. If Culmination is still free I will either try to use it on a rainbow, or it can be used with Rapid for 25-40% (depending on synth difficulty) progress, whichever is more useful.
Hope this is of some help.