That was my dream of burning EB points, but I never had the chance
On seatblock, me also have always in app check-in neighbour seat "occupied", but in practice most of times on NoRRA ATR there is a buddy next to me so they don't really care even if there are empty seats elsewhere. On Finnair flights it works amazingly well IME.
Best seatblock I have had a couple of years ago when I flew BA Y longhaul and I had a seat like 58Ö. Went back to the aft galley chatting with Y purser if there is any rows empty during boarding. He checked his pad, found one row, told me to install myself there in the middle and disperse my bags around seats and tell if anyone comes by that those seats are blocked. Yeah one guy was approaching me to share some space and I was hesitant not to be rude, but the same purser chap happened to pass by and just told the pax that those seats are blocked for Mr FFlash ^