Coolant leak from head bolt?

Great thoughts gang - I will in future use sealant on headbolts. However, I am having second thoughts whether the leak is from the headbolt or the ex. manifold stud. I haven't see any water/steam coming from or around the x-stud (this coolant leak only seems to appear at road speed), so I assumed it was a headbolt leak. But on closer inspection, the location of the coolant trail (white residue) could possibly be coming from either source. So I will rule out the x-stud first. Pulled it today, once dry I will re-seal with RTV and let it cure for a day and a half before refilling coolant and firing. Hoping this does it - will let you know!