I have just tested with EVGA 3G mini single fan as well.
But it looks like when I pushed core more than 135 the miner will crash.
At my current setting with +120 core, +120mem, 8 GPUs rig's stable at ~2336sol/s @85% power limit (average 290-293sol/s for each GPU).
Ah what's your GPU memory, Hynix or Samsung?
Btw, your payment fee is quite good, I need to pay roughly about 120$ for renting service.