the adhesion promotor goes a LONG way.. like a can for a whole interior.. it's like water, just a light coat over everything..
if your doing 4 door panels, a dash and other parts, I'd plan on 3 can's, maybe 4.. 1 can will do a pair of front door panels.. 1/2 to 3/4 for a dash.
so at least 2, maybe 4 if ya start throwing in ceiling trims, rear panels, etc.....
if ya want rattlecan, I strongly suggest the SEM... as some will remember, I HATE Duplicolor products.... most of their stuff sucks imo..