Fell down the rabbit hole

Welp, I let curiosity get the best of me and got into mining. I've been at it about a month now, first testing a solo gpu on my desktop daily driver, then building my own open air 6 gpu rig. I recently decided to open an account here because everyone here rocks (mostly.) I have found a plethora of good information here on these forums so I thought why not.

I am running a H81 Pro BTC R2.0 board, pentium chip, 1200 platinum psu, powered risers, Windows 10

4x Asus Strix Rx480 OC 8GB
2x XFX GTS XXX Rx580 8GB

I got 5 of them to play nice on 17.4.3 but can't get a total of 6. All equipment I tested and it's working fine, just a driver issue. From what I'm gathering on here it's a known driver issue. Anyway I'm going to be building a second, so I'll split off the 580s alone and get four more and get two more 480s for my first rig.

A couple of questions. Now that I have a stable rig, I'm looking to squeeze some extra hashing power. I'm not looking to have anything handed to me, I just want to know what bases to cover. I've already played with MSI Afterburner and have increased the core clock but it didn't do much for me (in terms of h/s).

Things I'm interested in:

• Flashing BIOS for my cards
  
• Undervolting (for energy consumption purposes)
  
• Overclocking (for h/s purposes)
  
• Known working 7 or 8 GPU boards for future builds
  

Can y'all point me in the right direction? Thank you very much in advance. I will have follow up questions if you have the time.