I got a 1/4" compression fitting, took one nut and ferrell off, got a flat washer and a hex nut to replace it as well as a foot of 1/4" copper pipe. thats for the stack side
got another compression fitting and a union for the hose side and they screw together.
drilled the stack and put the fitting in, actually reached thru the pipe where the baro fits and "quickly" installed the washer and nut from inside the stack.... my asbestos fingers sure did help as the stove was running and stack temp was 125.
its prob wise to idle it way down or shut it down for the less heat tolorant arms...
a extra measure was a dab of the seal-it-right around the fitting as Smitty did just because
hook up the hose and level and zero and Bam your in bizznezz