There's no reason a whm/smn can't use electrum rings too.
Anyway, I think you underestimate the importance of conserve MP. I can't find it anymore but there was a thread on the RDM forum showing someone's statistical test of Conserve MP; it outweighs Auto-Refresh if you are casting fairly often (RDM is the busiest caster in the game). Therefore it also outweighs ballad I (for yourself; but ballad I affects your party too).
Whm/blm: conserve MP, Warp, Escape, Elemental Seal (it works on Paralyze/Slow/Silence too). Magic bursts not a big factor due to whm's lack of elemental magic.
Whm/brd: ballad is like auto-refresh, but for everyone, not just you. Lower base MP though - you are giving up some of your max MP to ballad the rest of the party.
Whm/smn: higher base MP, auto-refresh. Summons pretty much useless, except maybe aerial armor. The level 30 /smn earrings are a nice perk.
Whm/rdm: lots of spell duplication. Fast cast, dispel at high levels. Generally not as good as /blm.
Anyway, I think you underestimate the importance of conserve MP. I can't find it anymore but there was a thread on the RDM forum showing someone's statistical test of Conserve MP; it outweighs Auto-Refresh if you are casting fairly often (RDM is the busiest caster in the game). Therefore it also outweighs ballad I (for yourself; but ballad I affects your party too).
Whm/blm: conserve MP, Warp, Escape, Elemental Seal (it works on Paralyze/Slow/Silence too). Magic bursts not a big factor due to whm's lack of elemental magic.
Whm/brd: ballad is like auto-refresh, but for everyone, not just you. Lower base MP though - you are giving up some of your max MP to ballad the rest of the party.
Whm/smn: higher base MP, auto-refresh. Summons pretty much useless, except maybe aerial armor. The level 30 /smn earrings are a nice perk.
Whm/rdm: lots of spell duplication. Fast cast, dispel at high levels. Generally not as good as /blm.
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