I find it easiest just to convert the tags from OPC to memory tags. No information in the tag config is lost in doing so (all of your OPC property config remains in v8, this was not the same back in v7!! ).
I use the python3 script in here to do this. Note it's python3 and therefore incompatible to run inside igntion. It will convert back and forth between opc and memory, and will only convert back tags that are actually opc tags, as opposed to converting all memory tags to opc, which would be bad..