I use the Weldwood stuff on darn near everything. It's the 'go-to'.
From just a light mist to hold scrim onto foam when doing pleats, to heavy coats when gluing vinyl roofs that have to stay in place @ 100+ mph.
It gets stronger with age.
Yes. I've used it for H/L's too. Especially custom ones with 3D details. That requires a foam heavier than the actual 'real' H/L material.
But it's age sensitive. The manufacturer says it's good for six months in the can. I've had a 5 gallon can last a year, no problem. After that, it starts to get a little too thick to spray through my gun. I just use an El-Cheapo automotive siphon style gun.
Smallest size I'm aware of is a 1 gallon can.
But for the average home workshop guy, even that may be too much, due to that shelf-life expectancy.
Although, when it does start to get thick, I use it for brush-on applications in tight areas or small jobs where spraying would not be feasible.
For a one-time job of doing a H/L in a personal vehicle, the 3M stuff, expensive as it is for a single can (I buy a 1/2 case at a time. 1 dozen.) it still performs the best in that situation.