Considering that the Lunar Opener starts pre-Eclipse and the Solar Opener invalidates the Eclipse by popping CA, its irrelevant what you do to your Mastery before any of these openers. Even if you somehow manage to time all this prepull to not lose any NG uptime it sounds like 99.9% hassle and 0.1% worth it.
Personally I have a small WA timer with a transparent background on the default Blizzard UI proc aura for SS. Clean and informative.