For AM3, inside your Autoexec.xml.
Code:
<register event="GainBuff_Aftermath:_Lv.3" silent="true">timers c Aftermath:Lv.3 180 down AM3.bmp</register>
<register event="LoseBuff_Aftermath:_Lv.3" silent="true">timers d Aftermath:Lv.3</register>
So, the gainbuff on makes it create the timer on gaining AM3. The lose buff deletes the timer when AM3 is lost.
The AM3.bmp bit in the gainbuff timer makes it use the AM3 buff icon on the timer. like so. 
spoilered for big.That file has to be placed in Windower4\plugins\icons manually, as the AM3 buff icon isn't normally in there. BGbucket didn't like my AM3.bmp, so I changed it to a .png. Will still work with timers, just change the .bmp in gainbuff to .png.
A couple of potential issues with geo buffs. First, buff names. A lot of geo buffs have the exact same names as the non geo equivalent. You may or may not run into that too often, but when you do, it'll mess with your timers. EDIT:The BuffIDs do differ, but I dunno if you can use buffIDs instead of names in Autoexec. Never tried it.
Next, gain buff won't trigger when recasting an already present buff and overwriting it. So your timer would just keep ticking down from the original cast.
Are indi spells static duration? There's not a duration listed in the resources. One thought was to have spellcast trigger a general indi timer when you cast an indi spell. That way recasting would overwrite the old timer. But that'd be hard to do if the duration varies.
Also, writing out a gain/lose buff entry for every geo buff would be annoying. <,<