I vaguely recall some testing that was done back at Corsair year 1 of this, maybe not be exactly what you are looking for but it should be in some of the earlier threads on this forum (not super early because all of those were "What kind of pirate are you going to be?" speculation). I don't have premium anymore so hard for me to search for it.
"Acid Bolt/Dia Stacking
I need to figure out how strong a QD'd Windshot will increase an Acid Bolt's DEF Down. I believe an Acid Bolt lowers DEF by 12.5%, but do not know the increase in potency a Wind Shot will grant. Is it a 5% increase like we see in Dia bolsters possibly bringing it to 17.5?
I need to figure out what Dia III and Acid Bolt stacking will do to DEF.
I need to verify that Dia III + QD'd Light Shot = 20% DEF Down in accordance with the QD tier upgrade. Currently it appears that QD'd Light Shot will increase a Dia to Dia II, Dia II to Dia III, and possibly Dia III to Dia IV power."
From: http://www.ultimals.com/forums/showthread.php?t=5551 Edited, Aug 7th 2009 11:28am by TheBarrister