oh, I forgot one:
some improvement can be achieved by making many reads, discarding those that are far from the norm and averaging the rest. I did that and made the mistake of using 'average' instead of 'norm'. The average was affected by the stray readings and made me discard the good ones on occasion. You need to compare in a way that gives you the average of those that are within a window, quite a fun piece of code to write since the location of the window is unknown.

Erik