Great job.
You have wooden box, so you may choose silicone rubber ( plate ) to glue it on wooden box frame.
There is one issue for RTV2 silicone, it is liquid silicone.
It is better to use food grade or white color.
In some cases, if you don't have idea about formula, then
A.
Color is milked in soap liquid, so, after soap dryer, silicone color is on soap. It is always happening for wrong formula.
This may only RTV2 with some essential oils to be a chemical action.
B.
How do you know what is inside of your RTV2?
BPA Free?
I don't have answer either.