The regression of average slope on LenInt is slightly better WITHOUT logs.
But note that corresponding to the fairly strong direct correlation of AvgSlope wiht LenInt, there is ALSO a fairly strong inverse correlation of Mean(u') with LenInt.
I THINK this result means that at least in this case, your current definition of average slope is "OK", because the means are varying systematically, not arbitrarily at my "whim", to use your piquant expression.
But I'm not at all sure of this conclusion, so I'm anxious to get your evaluation of this situation. Is your definition of average slope "OK" or not?
Or can you not tell until I?ve obtained the data for all the cells of the current model? (Note: ?current? here means without uL/uH dichotomy.)