I've not looked at the specific game in question, but in general, doubling the thinking time leads to a very notable strength improvement regardless of the base

I've not looked at the specific game in question, but in general, doubling the thinking time leads to a very notable strength improvement regardless of the base level of play. The increase becomes slightly smaller at higher levels but does not really diminish, and it currently looks like the ceiling is still a bit away. If it is "only" 4x3090 at 16s, you will definitely get a drastic playing strength boost from doubling the thinking time. This is still clearly within the interval of a linear relationship between thinking time and playing strength, i.e. elo ~ log time. The relationship, to my knowledge, becomes less clear only starting at about 10-20x the number of playouts. Source: Wrote a paper on this. https://ieeexplore.ieee.org/document/10645535 https://ieeexplore.ieee.org/document/10645535