Much better CPU temps there Wolfe. 65-70C at full load is normal. 
You can try pushing it to 4.2 if you like, I reckon you may be able to do 4.2 with 1.210v, but 4.4 may require a tiny bit of extra voltage. If you bump the voltage up a tiny bit (try 1.220v for 4.4 perhaps) you shouldn't notice your temps increase too much, maybe by about 2C or so.

You can try pushing it to 4.2 if you like, I reckon you may be able to do 4.2 with 1.210v, but 4.4 may require a tiny bit of extra voltage. If you bump the voltage up a tiny bit (try 1.220v for 4.4 perhaps) you shouldn't notice your temps increase too much, maybe by about 2C or so.