Setting Power Zones on Karoo 2?

New two Xert and have a question about using my TP to setup my head unit on my bike. Currently using a Hammerhead Karoo 2 and really like the graphic power meter which makes it’s easy to see which power zone I’m riding in at a quick glance. My question is should I be setting my FTP on my Karoo = to my TP on Xert and if so, should I update my Karoo FTP setting every time it changes on Xert (which seems often)?