try
+125 core
-500 memory
70% tdp
I think you will get around 465 sols and save power
I have actual +200 core and +750 memory with 70% power limit on G1 card, and is doing 455 sol/s best.
Whenever I tried to go down in core clock it lost 60 sol/s for -120 core clock and it lost about 85 sol/s when I switched from +750 memory to -500 one.
I think staying in the plus both in core and memory with 70% power limit should be the best settings.