you have the right things up in maxim Logan, and the offset is about right, but it all comes down to your gain aswell. If you have followed the guide to the letter, then you need to tweek your offset just a wee bit more but its a tweak. Ill do some screen dumps now of the histogram i was talking about.
No calibration Gain 0 Offset 118
Calibration Gain 17% Offset 116
Like i said you can notice the distinct difference in the shape of the histogram with almost 100% of the data Landing under saturated. Where as the non calibrated is topping out at just on 1000 pixels and a fair bit of the main neb landing in the saturated area.
Also to note that the calibrated image was done with the 254 and the non calibrated with the ED 80 which has a considerable downgrade in F ratio and light capturing capacity. Both images where Luminance, both images where 10 min.