Keerthi suggested using 16O5+ for optimizing the source. I did a tight mass scan in that area, and 16O5+ is clearly visible. I will use it for some source tweaking. Also, I used Gabe's calibration program to slightly adjust the values of the two constants. There are some 10nA of 16O5+ on FC6 presently. Final settings for today, etc. are attached below.