Did all of the Hampton/Regency owners out there buy the flue collar adaptor from Regency, or did some of you just use the adaptor that came with your liner (those of you that diy'ed and bought your own liners)? I'm planning on buying a 5.5" ss liner and wondering if the adaptor is a must or if I can use something else. All of Elk's posts say to buy it from them.