RX580 Mining Question – Low Core Clock, Stock Mem Clock?

Hi, I have a Sapphire Pulse RX 580 4GB, and mining at 888MHz (Set at -35% on AMD Wattman) but I keep everything else stock (Memclock is at 1750MHz) and I already get expected hashrate (11-12 MH/s) for this card. Only when I turn down my Memory clock I get lower hashrate.

Is this a good configuration? My temps hover at 69-72 with 45% fan (this is the highest I can deal with if I want to sleep or work while it's mining), is this ok or should I aim lower or repaste my GPU?

I'm asking because everyone seems to be running at 1150 core / 2000 mem for this card and alao undervolting them (I find it pretty tricky, any undervolt I made would just crash the card), and when I set it too 1150/2000 I only got the increased heat not the higher hashrate.