Nezea,
Tarutaru SCH75/RDM37 has the following stats, plus the gear you listed to attain a 1700+ Blizzard IV.
132 INT Max = 77 Base, 36 Gear, 7 Food, 5 Merits, 7 Lv5 Stormsurge.
MAB = 36 Gear, 20 Red Mage Sub.
10% Increase for Ice Weather, Forced with Obi.
20% Increase for Ebullience.
15% HQ Staff Increase.
And, 10% Critical Hit Bonus.
I was able to nuke Blizzard IV for 1810 Damage. (1508 without Critical hit.)
BLM/RDM has 2 INT higher. Minus the 7 INT Stormsurge bonus.
To keep things on a level plane, a BLM wearing the same gear, effectively making it gimp would achieve a 1648 Blizzard IV with the 10% Day Bonus but without Critical Hit damage. 1812 with critical hit.
This is not counting Sorc Ring (INT -5, MAB +10) possibility which would place BLM/RDM numbers at 1711 / 1882 with Critical Hit.
Monster Target is Ebony Pudding with no Burn.
Even with best gear, Ebullience will only make a SCH catch up with a BLM wearing the same gear.
Edit: My numbers are possibly off by 1 INT in the damage calculation since I didn't factor in where your 1700+ Crit hit bonus came from.