A thread from long ago caught my attention. Perhaps you might find of interest the slide presentations at the following links:
http://www.threeimpacts-twoevents.com/wp-content/uploads/2013/01/SIMULTANEOUS-IMPACTS-3JAN2013-WEBSITE.pdf
http://www.threeimpacts-twoevents.com/wp-content/uploads/2013/01/COMET-IMPACT-ANALYSIS-AND-EFFECTS-3JAN2013-WEBSITE.pdf
Reference post #89. I believe FReeper gleeaikin may have a greater interest in this sort of stuff than me.