Not sure if you want outside feedback, but:
Defensive:
http://lucy.allakhazam.com/spell.html?i ... ource=Live
Stonewall:
http://lucy.allakhazam.com/spell.html?i ... ource=Live
Basically tradeoff is snare versus doing less dps.
Evasive:
http://lucy.allakhazam.com/spell.html?i ... ource=Live
There's a long discussion on tanking mobs on the steelwarrior site at:
http://www.thesteelwarrior.org/forum/sh ... d.php?t=13
Basically boils down to mobs hit in a range of 20 hits. They have a damage base and 20 intervals, so the minimum hit you see is Damage Base + 1*Damage Interval. Maximum hit is Damage Base + 20*Damage Interval.
Stonewall and Defensive only affect the 1-20 range of Damage Intervals, they don't touch the Damage Base. So for mobs that have high Damage Bases in comparison to Intervals, Evasive is better. They use a 0.13 ratio as a rule of thumb.
Shielding %'s affect the Damage Base only.
An example in values? Mob A hits for 1000-2900. So damage base = 900, Damage Interval = 100. Ratio of 100/900 = 0.11.
Stonewall and Defensive affect the 20*100 range, cutting it down 45%. I can't remember offhand how that works but someone can read it, for speed say though 45% of 2000 = 900. So now the mob hits from 965 to 2000. If the tank had 10% shielding, that takes 90hp(900 damage base *.10=90). So 875 to 1910 hps range.
Mob B hits for 886 - 1000 (aneuk twins in Txevu, very rough numbers). It's Damage Base is 880, Damage interval is 6. Ratio is 6/880=0.0068.
Stonewall, defensive affect the 120 range(20*6), 45% of 120 =54. So using it the mob hits from 883 to 946. 10% shielding on the tank = 880*.1 = 88hps off each hit in comparison. So, using Defensive/Stonewall on that kind of mob is useless in comparison, a tank with about 6% shielding using nothing is the same as a tank with 0% shielding using Stonewall. Better still to use the better shielded tank + Evasive Discipline.
A few of the Ikkinz golems you've already encountered seem to have those small ranges of hits, where they hit from 1900-1950 it seems.