I have the following questions about an RTX 2070 Super Ultra FTW3, my new graphics card:
 
(1) Is it safe to establish, in 'EVGA Precision X1' and 'MSI Kombustor', a Memory clock of +640 (the standard Memory clock is 1700MHz), if both PC games and software applications like Kombustor/RivaTuner or Eunigine do not show any artifacts, or overheating / shutdowns?  
 
(2)  Along with the offset under (1) above, is is safe to also raised the GPU clock with an offset of +120, thereby raising the GPU clock up to 2100MHz / 220MHz (or so) with boost during gaming? 
 
(3)  Is the following fans' curve acceptable? >> I keep my three GPU fans at '0' RPM up until 55C, then they move to 30 RPM at 59C, then 54 RPM at 65C, then 75 RPM at 80C, and then to 100 RPM. The GPU remains stable at 60C - 64C...   I want the fans to say in 'quiet' mode until the GPU temperature reaches 59C.  Should the fans instead start kicking in before they reach 59C?
 
Thank you for answering my questions.  I want to enjoy my new GPU but also want to make sure I overclock responsibly.  And again, so far, I get stable temperatures and no crashes, everything works very well. 

Sounds acceptable to me too, but you said 'RPM' when you really mean 'Percent'..Personally, I would have the fans running at 100% a little sooner, maybe 70C or so if fan noise doesn't become objectionable, if the GPU ever even reaches that temp..Up to you though.