So I’m building a new fireplace wall and ended up moving my existing heat n glo 6000trb out about 10” from where it was before and I am having the damnest time finding any 5x8 5/8 vent piping. I’ve been scouring every website and forum and there’s only a handful of people even talking about it. I usually don’t post on forums but I really don’t know what to do at this point. If you guys have any answers or recommendations I would really appreciate it. Thanks