Sooo, to get things straight, I can use it the way I wrote it, right??? Spreading them out doesn't mean 2 back to back days now and 2 days later?

And also, can I purchase it now and activate it 4 months later or is it better to purchase it closer to my travel?

That's correct, you may use it that way.

It's possible to buy it now but there's no need to do so. 

Activation / use must take place after 11 months at the latest.

You can wait for a promotion. In some years there was one around valentine day. Just subscribe interrail newsletter to get informed.

Thank you guys you've been very helpful !