Gamefaqs ausserdem gibt es in diesem Forum diesen Thread, der sich wie man am Threadtitel erkennen kann, mit den Klassen (Jobs) beschäftigt.

F. Red Mage
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Ah, the Red Mage, the jack of all trades. As a rule though, the Red Mage loses
his strength in melee in the higher levels, and becomes more of a mage type
which is used for spells like Refresh. Remember, at higher levels melee subs
really lose their value, so I'll only put mage subs again. Subs such as Thief
and Warrior might be fun early off, but later they'll be doing very small
damage and will only be decent to get hit with when under Stoneskin/Phalanx. So
remember, Red mages can potentially be all right melee players at higher
levels, but they'll need constant buffs like the En spells that make them more
trouble than they're worth.

--a. Red Mage/Black Mage--
It may seem repetitive, but actually it's a very good combo which specializes
in attack magic and enfeeblement. With convert and refresh from the Red Mage
job, and the benefits of group spells, INT, and MP from Black Mage sub, this is
a very viable combo.

--b. Red Mage/White Mage--
Very similar to Red Mage/Black Mage, but this combo specializes in healing and
support, which goes very well with Red Mage's strength in enfeeblement. Better
MP and MND than average, and the group curative spells from White Mage makes
this job a very loved job in parties with Convert and Refresh.

c. Red Mage/Summoner
Fairly bad... Half-level summons and only benefits being an MP boost. It's much
better to have a subjob such as Black or White Mage.

d. Red Mage/Bard
This is actually a possible combination, but again Bard is really nerfed as a
subjob. Most parties would prefer a Bard/Red Mage to this combo.