corsair c70 case cooling

Heya, (war and peace below)

Firstly! Good Choice, I have the same case, and couldn’t be happier.
Firstly, as you should probably be aware, the tool-less case has plenty of room for filling with your shiny and glowing fan set ups. 3 standard (120mm) and 7 more mounting points including a dual 240mm rad spot on the top, and if you are feeling lavish, removing the bottom HDD cage, allows you to fit an additional 240mm rad, allowing for a crazy dual loop setup!
You need to make the decision whether or not to go for positive or negative pressure, which both have benefits and disadvantages.
Positive pressure (assuming fan filters aswell): Inside case stays cleaner, as the only air coming in is goes across filters, and the exhaust blows out only, any excess will squeeze out all the wonderful cracks and crevices your case has
Negative pressure: better cooling generally as you have a constant airflow stream through your case but the vacuum caused will pull in excess air through those same wonderful cracks and crevasses. The aim is to have more air forced out of the case than being forced in, causing a vacuum, which produces a steady stream of cooling air, this is good for getting air to the areas no cooling air can get too.
So my recommendation will be something like what I have done, by assuming that normally air is usually exhausted through top mounted “blowhole” fan(s) and the rear exhaust. This will leave you with the front 2 fans (on the HDD cage) or 4 fans depending if you pop off the front cover and put 2 more in drawing air across your GPU, 2 spots on the side window drawing in, and 1 on the bottom in front of your PSU drawing air into case (big filters free with the case on the bottom)
Then on the top, you can mount two of the “blowhole” fans, blowing hot air out of your case, and the exhaust doing what it does best, dumping hot air out the back,
This set up, will suck in air from the front and side of the case, and spit it out the top, leaving very chilly components 
I have my processor cooled with h100i water closed loop, and I mounted it so it draws in through the lid, allowing me to put two more fans on top, pulling more in, forcing my exhaust fan too try to dispose of as most hot air as it can, silly me, if I was to rebuild my tower, I would consider my above statement haha.
Good luck, get some piccys of the finished job!