I jumped into 70 content right away with SGE and purposely avoided lower levels as that is what works best for me, but I did notice that burst healing took a little while to figure out. Eventually I settled on Krasis combined with Taurachole + Druochole + Druochole (+ Rhizomata and another Druochole if available). At level 90 Pnuema enhanced with Zoe helps immensely.

Don't be afraid to spend resources to you can regain quickly. Addersgall ticking up every 30 seconds means that you can use it pretty liberally, and you can use non resourced based abilities to fill in any shortage of Addersgall that you might run into.

Also don't overlap Taurachole and Kerachole as the defenses don't stack. It's sometimes tempting to do this if the tank is taking more damage than needed, but you would be better off using Holos if Kerachole is still active on the tank. Soteria is also rather strong as a filler between other skills and available at low levels.

SGE has a good set of abilities and you'll find a use for most of them. Pepsis will be the exception not because it's bad, but because it's more niche than the rest. Use it if it's useful, but learning the other skills takes priority in my opinion.