If I wait a beat after the tsuke, is applause acceptable at any scene?

"Wait one beat" sounds plausible but measures the wrong thing. What decides whether to applaud is not elapsed time but whether the play has reached a break there. A tsuke can sound while the scene continues; a scene can close cleanly with no tsuke at all.

You can see when a moment has closed. The actor freezes in a mie. He withdraws along the hanamichi. The striped curtain is drawn across at the end of an act. At such moments even immediate applause is received as part of the play — indeed, a silent house at those points leaves the stage feeling rather alone.

There are also moments that have not closed: the hushed passages of a kizewamono, the descent of feeling mid-scene, the air drawn taut toward a line still to come. Here, applause breaks something no matter how long you have waited. There are scenes where continuing to listen in silence is the greater respect — true of theatre generally, but the contrast is unusually sharp in kabuki. When unsure, move with the house; that, in the end, is the etiquette of the theatre as a shared space.