Best practice is to Test in Small increments
Yes - add them Manually, then: Apply, then Save --> to a profile number you had previously selected
Yes - Max Temp & Power Targets (full is OK)
Yes, you can try - stability issues with the auto test could happen after raising Targets or RAM Clocks
Auto test does Not test RAM
Test @ base - find best OC that is stable ---> then start bumping the Voltage & see if you get better OC
Once you find the Max OC - back off the settings 5% -10% for Stability
Best to run a benchmark - they are a consistent way to load your PC while making adjustments
Your Max OC may not be stable in other games
Max MHz is Not always ---> Max Performance