/assist focus
/cast Amplify Curse
/cast Trinket1
/cast Trinket2
/castsequence reset=target Curse of Agony, Corruption, ....

This should fire anything that is ready to be fired again. you can fire a trinket as well as anything in the castsequence at the same time, I think the same goes for amplify curse. This may be a noisy setup but it will always keep everything up. I'm worried that a long cast sequence can't be made silent unless you are using Trinity or something that allows for longer than 255 characters in a macro. I currently have my shaman silent trinkets