Hey CharonX, thanks for the interest
Friends are certainly the easiest way, though a majority of those splitting the second tier are finding each other in online communities, wherever they happen to hang out and share an interest in roguelikes. I've seen many such groups form on various forums, and in each case one person buys it and the other two repay them either via PayPal, or sometimes using other methods like gifting Steam credit or some other game on Steam. Then of course there are the generous backers who are just buying the Improved Tier and handing out the other codes for free
The forums here aren't a great place for this, because pretty much everyone here already has it