I've had Yew shift on me despite being left overnight (it was steam bent)
.
D'uh, C'mon guys it's self evident that leaving it clamped won't make any difference if it didn't get hot enough!
BUT... it won't do any harm to leave it clamped up for a day or so unless you are busting a gut to get it done.
Why risk spoiling your work through haste?...After all it was probably haste that stopped it getting hot enough in the first place.
I've done it often enough and learned my lesson.
Of course I reserve the right to be talking out of my backside, but
I'll still be leaving any bending on the caul for a least 2 days.
Del