Citation in "the hole"

This months landing challnge has it all going on. Having not flown the citation or the approach before, it was real high pulse rate fun. I might have been more on the c/line if i’d got it trimmed earlier. I noticed some pitch resonance on the way in that was hard to settle without adding power, is that my problem, too near the floor ? Can any fans of the a/c comment?
Also what’s the ground roll number made up from is it deviation from c/l and how short you can stop ?
Love these short scenarios really well thought out and gamified.