About a year ago I signed up for MintedPoker (40% RB through my affilite) and logged in to see that there were under 1000 players at peak North American times. Unfortunately with so few games going ever, 40% Rakeback on $0 rake is still $0.
Think you will have a hard job to find these overlay tourneys these days. poker sites that these games used to be found on,have realised that by making them re-buy's,then they are more than likely to reach,and exceed the guaranteed figure.
They don't like to give much free $ away these days.