Looking for some info before I pick up my Heritage pellet on Thursday (first pellet stove). What dimension corner hearth pad should I use? Building my own, so open to ideas. And both 3" or 4" vents are suggested in manual, but which would be preferred for a horizontal corner install (a single 45dgr to straight pipe)? Thank you in advance for any advice you could lend. I know very little about burning pellets, outside of what I read here!!