~ Also I just exchanged my 1,600 RP for 500% bonus on the minimum free FREE BTC reward, and now it's 0.00000324 BTC for me, which is not bad.
You should go for the 1000%. Higher than the second-last tier reward

Yeah, I was doing that in the past, but right now I don't have enough Reward Points for that. And regarding the second tier, sometimes I hit it and get the reward without any RP paid

Well, I haven't been to FreeBitco.in for a few years. It turns out that right now I have 10k satoshi in my wallet and I earned 0.04506873 BTC in total through my referrals with whom I shared like 0.02440395 BTC. I have 120 referrals since the times when I had been actively using this facet, and a couple of my referrals are still active (this 10k satoshi came through them, most likely).~
120 referrals is something I can't even imagine how to get. From my experience, people never click ref links, and thus I have zero referrals. How have managed to get that much?