I see and I think I have done that before, but don't you think that slots take the chosen stake amount into account when it comes to hitting the bonus free spins or not?
Yes, the do not. My strategy is more of hope. If I do hit the bonus buy with a much higher stake the reward I will get on the free spins will be higher than with a lower one.
Most I've gotten is a 3-figure win, really lucky to get to 4 figures. I'm sure we'll have gotten much higher from players here, but they may not share for privacy reasons.