I use the stuff that comes in the bottle with that name,,,,,"Mr Primer Surfacer 1000",,,,,,,I couldn't get "Mr Leveling thinner",,,,,,so, I thin it 50/50 with Tamiya "yellow cap" Lacquer thinner,,,,,,,,,maybe decanting your's from the spray can and thinning it 50/50 with Lacquer thinner will let you use it up without having to throw it out
my mix works almost the same as the Alclad primer
Rex