All Tanks are equal.

[Ironos]

Sorry but if i remember correctly one patch note they say more than 2 melees dps Or casters afect your LB

I believe they did that in 3.1 (?) and then quickly reverted it. In 3.2 they made so that if you have 2+ of the same job and/or you break the 2/2/4 composition. Likely to try and discourage solo tank/heal comps and bringing an extra DPS.

Side note: 3.2 also made it so doubles in DF solo content no longer slow LB gauge.

Edit: Exact wording:

Dungeons and trials accessible solo via the Duty Finder:

• The Limit Break Gauge will no longer fill more slowly when multiple members of the same class/job are in the party.

Dungeons and trials requiring a full party to register via the Duty Finder:
The Limit Break Gauge will fill more slowly under the following conditions:

• Three or more party members are playing as tanks.
• Five or more party members are playing as DPS.
• Three or more party members are playing as healers.
• Two or more party members are playing the same class or job.