for selecting the most attractive location (I assume that is meant with “nearest best placement”) you can use this code instead of the roulette wheel:
// — select the location with the highest attractivity —
double tempBest = 0;
for(int k = 0; k < AttractPop.Count; k++)
tempBest = AttractPop.Max();
slot = AttractPop.IndexOf(tempBest, 0);
The peaks in the plot show that the selection prefers for a while only one location.