One can goes a long way! One quart will finish:
1 acoustic guitar body and neck
2 complete mandolins
2-3 solid guitar or bass bodies
3-5 electric guitar or bass necks
2-3 banjo rims and necks
Keep in mind there are many application variables: your spray gun adjustments, PSI used, and the number and thickness of your finish coats.
Lacquer products are flammable! They cannot be shipped outside the USA, nor shipped by air within the USA. Nitrocellulose lacquer products should not be used with acrylic lacquers.