As an example for a macro I see skip lines:

/micon "Stone II"
/merror off
/ac "Stone III" <t>
/ac "Stone II" <t>

I know I can't queue it, so it's suboptimal, but the idea is that I don't ever have to change buttons depending on what level I'm synced up or down to. I see this macro skip lines and throw out the lower spell every once in a while. It happens less if I double up the ac lines for each, but it's not foolproof.