With the addition of several pieces of gear for GEO that offer the possibility of maximum avatar perpetuation reduction (3 pieces of Hagondes set would do it) I started to theorycraft a bit. I'm assuming that the buff timer durations are based on the summoners level, so 49 SMN would require +30 Summoning Magic Skill in gear to cap their durations due to having 150 base skill.
30s Base Duration Buffs - 1min cap
Crimson Howl - AoE Warcry
60s Base Duration Buffs - 2min cap
Rolling Thunder - AoE Enthunder
90s Base Duration Buffs - 3min cap
Hastega - AoE Haste
Glittering Ruby - AoE Random stat+
Lightning Armor - AoE Shock Spikes
Frost Armor - AoE Ice Spikes
Aerial Armor - AoE Blink
180s Base Duration Buffs - already capped
Noctoshield - AoE Phalanx
Ecliptic Growl - AoE Stats +
Shining Ruby - AoE Protect/Shell effect
Other Useful Abilities
Earthen Ward - AoE Stoneskin (15min)
Spring Water - AoE Heal & a -na/Erase effect
Whispering Wind - AoE heal
Healing Ruby - Single Target Heal
ItemSet 318431
Plenty of ways to cap buff timers for GEO, mix and match any of the above for 30 skill. There are other pieces that offer less in each slot as well.
Blood Pact timer delay pieces are the main issue here with only the magavan slops being available for -2s. Likely you'll only see yourself cycling 3 buffs.
I could see starting out with buffing with Earthen Ward then cycling Hastega, Ecliptic Growl and Warcry for your party if going all out attacks. Hastega is amazing in MP conservation. You can Haste 6 people for 129MP, it would take 240MP to Haste a full party otherwise. It lasts for the same duration and gives the same 15% as the spell Haste.
Noctoshield, Shining Ruby, Earthen Ward would probably be ideal for going all out defense on fights where surviving is your primary focus. Various other buffs/heals used as needed.
For fights that deal damage that is spread out amongst targets keeping an avatar out would greatly help the party as well. I'm talking about moves such as 1,000 Needles. For perpetuation, you have a large array of possibilities. Easiest way would be to augment any 3 pieces of the Hagondes set with -5 each.
While this is intended mainly for GEO this could still be applied to SCH and RDM with a few differences; SCH wouldn't need to use Earthen Ward for example.
So what do you think, would it be worth a consideration in some fights now?