the problem is that you simply cannot in any way assume that the "apparations to ticks" ratio would be even close to equal for every involved priest. since it differs vastly due to movement (and hence playstyle)
the more acceptable way of guesstimating this stuff would be via getting the apparation's damage, re-calculating how much dmg an sw
from the same priest would do (though even that leaves you with 6 range options, based on combinations of imp. sw
, lack thereof, and the glyph) and then going back through extra tick-logs to find the last tick (and by that priest) fitting either of those damage ranges.
yet, between speccing, glyphing, gearing, procs and whatnot even that would be inaccurate as all hell.
long story short...guesstimating on meters is nothing short of unacceptable, since it kind of defeats the purpose.