Only Z270-P, use m2 slots for PCI-e. Z270-A not enough bus width to connect 8 cards
thus is what I watched
This is a very good video looks very professional and they look like they no what they are doing
For any one that need help putting 6+ rings on any of the two have a Z270
It did look like it can be done
https://m.youtube.com/watch?v=DR-FkpU2KfIAm new to all this so I cant say that this is 100% right
Am only going on what I have watched
BBT is pretty well known.
Take a look at their store will give you ideas on what you can use.
Here's another video to show that the Z270A works.