table selection calculations, thoughts wanted

[Paul2432]

I've been giving table selection more thought lately. I've kicking around some numbers and assumptions to try to quantify the effect of having good players at my table.

Suppose a player has a 15% ROI. On average, the other players at his table will have a -11.8% ROI. Now suppose one of those average players is replaced with another 15% ROI player. If we assume the bad players stay constant at -11.8%, the two good players will now have an ROI of 1.6%. If a third 15% ROI player sits down, the three good players will now have an ROI of -3%. (note that 10 equally skilled players will have an ROI of -9.09%)

Of course the assumption above that the bad players hold there ROI constant when another good player sits down is probably false. If we assume the good players hold ROI constant, then with two good players, the bad players ROI needs to decrease to -15.1%. With three good players, the bad players ROI needs to decrease to -19.4%.

My questions then are:

1) What is the best way to model the impact of a good player taking a seat at your table?

2) If you sit down for a SNG, how many known good players would need to take a seat before you get up?

Paul