Here’s a comparison for you....

Tamiya Gloss Coat 10ml brush on. Up to 4.00
The same in a 100ml spray can. Up to 9.00
Pledge Floor polish liquid. 800ml for up to 14.00.

all prices quoted are from Amazon Prime UK.

800ml in the 10ml Tamiya jars would cost you an eye watering 160.00. The same volume in the Tamiya spray cans would cost you 64.00.
To be specific, you need the clear liquid Pledge product called “Revive It Floor Gloss”.
The Pledge product is what used to be sold as “Johnson’s Klear” and is without doubt the best I have come across for a clear coat. It can be sprayed undiluted through an airbrush and brushes on without leaving any brush marks. Clear plastic parts such as canopies come up gleaming crystal clear and look like real glass. Decal placement and adhesion is improved with a light coating and a further coating once the decals have dried seals them nicely. Cleaning airbrushes and bristle brushes is a cinch using warm, slightly soapy water.