How to check if a crack is ready
 

How much do you expect a crack to be closed before it is time to apply or press in the glue, please?
Can a crack be too closed up, for that?
How do you check that?

Regards

Its not really about how well the crack has closed up, its really about the guitar being at a stabilised temperature and humidity, once it has an ideal temp and humidity the existing crack be it tight or loose can then be glued up.

Steve

Thank you. that will then be when the instrument has a humidity of 50% at 68 F (20 C), supposedly?
Regards

Correct, once the instrument has stabilised you can if its a wide open crack, insert a piece of wood, if its a tight crack, pressure inject some glue in

Steve