I did this stuff before I ever got melded i90 accessories. Just hit a dummy as a Pally until TP hit zero. The small difference between adding 90 STR and 60 STR makes me think I did something wrong, though.
Edit: Yep, these are bad tests because they screw with secondaries too much. They're still sufficient to show that STR counts, though.
Test: Halone until TP is gone and cooldowns on cooldown.
Situations
Shield Oath: Act as if I've just pulled: FoF -> Shield Lob -> Rotation
Sword Oath: Act as if I'm OT: FoF -> Rotation
Why PLD?
1. PLD DPS is super easy to optimize and impossible to screw up.
2. My WAR isn't at 50. (Well, it wasn't when I did this. It is now, at the time of this post!)
Weapon: Diamond Brand
Shield: Diamond Shield
Full VIT, Full Parry
Test 1: Shield Oath
428 STR
395 Crit
221 Det
410 SS
590 Parry
Duration: 2:38
Total DPS: 169.99
Test 2: Sword Oath
428 STR
395 Crit
221 Det
410 SS
590 Parry
21
Duration: 2:49
Total DPS: 259.72
Weapon: Diamond Brand
Shield: High Allagan Shield
All DPS Accessories. Four 110's and one 120 increase STR by 93. Switched HA Boots for Noct Boots for Determination boost. This emulates the decision to wear Pentamelded i90 + 30 bonus points in STR.
Test 3: Shield Oath
521 STR
418 Crit
280 Det
401 SS
499 Parry
Duration: 2:36
Total DPS: 215.67
Increase: 26.47%
Test 4: Sword Oath
521 STR
418 Crit
280 Det
401 SS
499 Parry
Duration: 2:48
Total DPS: 320.30
309.55
Increase: 23.32%
Conclusion: 93 STR and a small bit of secondary swapping increased my DPS by approximately 24-25% overall.
A mix of DPS Accessories and bonus stats to increase STR by 65. This emulates the decision to use pentamelded i90 while having bonus points in VIT.
EDIT: Well, it was supposed to be 65 but it's actually 68. Coincidentally proportional to the first set having 93 instead of 90.
Test 5: Shield Oath
496 STR
399 Crit
268 Det
401 SS
532 Parry
Duration: 2:40
Total DPS: 206.47
Increase: 21.46%
Test 6: Sword Oath
496 STR
399 Crit
268 Det
401 SS
532 Parry
Duration: 2:50
Total DPS: 305.68
Increase: 17.69%
Conclusion: 68 STR increased my DPS by approximately 19% overall.
Bonus finding: It would appear that the extra STR is increasing Shield Oath DPS more than Sword Oath DPS.