Code:
[16:41:05]The Merrow Shadowdancer uses Gusting Gouge, but misses Kehhiko.
[16:41:08]Kehhiko hits the Merrow Shadowdancer for 65 points of damage.
[16:41:08]Kehhiko hits the Merrow Shadowdancer for 51 points of damage.
[16:41:09]The Merrow Shadowdancer hits Kehhiko for 32 points of damage.
[16:41:09]Additional effect: Kehhiko takes 5 additional points of damage.
[16:41:12]Kehhiko uses Trick Attack.
[16:41:12]The Merrow Shadowdancer misses Kehhiko.
[16:41:13]Kehhiko scores a critical hit!
[16:41:13]The Merrow Shadowdancer takes 431 points of damage.
[16:41:13]...A command error occurred.
[16:41:14](4*) You were unable to change your equipped items.
[16:41:14]Additional effect: Treasure Hunter effectiveness against the Merrow Shadowdancer increases to 8.
[16:41:15]Kehhiko defeats the Merrow Shadowdancer.
[16:41:15]You offer to trade with Vermy.
[16:41:32]Vermy starts casting Sneak on Vermy.
[16:41:43]Vermy starts casting Invisible on Vermy.
[16:41:44]Kehhiko uses Spectral Jig.
I left in excessive extra code to show that there were no post-kill overflow attacks, and that the TH+ actually proced on a killshot. I was very surprised, since add effects usually wont kick in on killshots.
Test 3 is up, and there are some numerical discrepancies, in favor of test 1. Ideally, the TH+ rate should have been the same as Test 1, going from TH3 with TH3 in gear as going from TH6 with TH6 in gear. Possible problems include: sample sizes, day/moon phaze (here we go again), the difference in TH level (going from 3 to 4 would be a greater increase than going from 6 to 7), but most likely being stats on the gear (Haste set = STR+30 DEX+30 VIT+8 AGI+24 MND+5 Triple+3 , TH set = STR+27 DEX+12 AGI+28 MND+2), the former set leading to faster kills with more multi attacks (meaning less TH+ proc chances). Test 1 parsed 10397 attack rounds in 176 mobs (59 attack rounds per mob), yet Test 3 parsed 9805 attack rounds in 205 mobs (48 attack rounds per mob). That average of 11 less TH+ proc chances per mob could have gone a long way.
I think the more math inclined can figure out how to factor in the proc chances with the TH+ results of Tests 1/3, but I think they're pretty similar.
Test 2 is pretty definitive that the TH+ proc rate is helped by wearing TH+ gear once you get further up (presuming you dont pre-stack it).