You should activate cleric stance as normal, only cos it is situational and sometimes you may activate it with a macro when you dont want it to.. but this is my dot macro:

/micon "Virus"
/ac Virus <t>
/ac Virus <tt>
/wait 1
/ac Bio <t>
/ac Bio <tt>
/wait 2
/ac Miasma <t>
/ac Miasma <tt>
/wait 3
/ac "Bio II" <t>
/ac "Bio II" <tt>

<t> is for when you are targetting a mob, good for soloing of if you group is sturdy and you dont have to target your tank constantly.
<tt> is "target of target" therefore if you are targetting your tank it will ignore <t> and shoot at his target instead.

I also have <tt>'d :

/micon "Ruin II"
/ac "Ruin II" <t>
/ac "Ruin II" <tt>

and:

/micon "Energy Drain"
/ac "Energy Drain" <t>
/ac "Energy Drain" <tt>