I use Rapid Synthesis x4 to start off my progress so it allows me to save CP overall. Also I will refresh Comfort Zone throughout the synth if I have enough durability and CP to get full use of it. I tend to use Master's Mend II twice or even three times in the entire Synth if I happen to have 240+ CP after the hasty spam following the first Master's Mend II. Apply Comfort Zone before each Master's Mend II if you have 240+ CP remaining as well.

Another thing, don't bother using Steady Hand II if you have less than 50 durability left on the synth unless you're going for the Byregot's finisher shortly afterwards. Sometimes it's best just to let your hasty touches go without it to save CP for another Mend II.