ok, I was finally able to get the redundancy stuff to work on the opc side. It took a little bit of scripting to get it to work like I needed. basically I had to setup a opc-ua wrapper on the backup so that I could turn the opc server on/off depending on the computer name(couldnt get opc-da to connect remotely to the backup machine for some reason). if I am on the master, I use the opc-ua link to write to the backup server off tag to turn it off. If I have a failure on the master, once it swaps over it writes via the normal opc-da to come back on since this opc-da stays active during swapover. I then have a script that looks at the status of the master opc server, and if the heartbeat fails, it stops the gateway(which also stops the master opc from continuing to poll), which forces a swap to the backup . Once I start the master up again the computer name script turns the backup opc off via the opc-ua link .
sounds confusing but it works! This is just a test scenario, if mplemented I would probably also add some stuff in scripting to make sure that the backup opc and gateway was active before trying to swap over.