Which size of cornice should we get?

If the installation space is small or the ceiling height is not high enough, it is better to use 9 and 7 cm cornices, and if the ceiling height is more than 3 meters or its area is more than 100 meters, cornices with a height of 15 and 12 cm should be used. cm will be a good choice.

For installation, wood glue and a type of screw called TN screw are used.