What worries me is that there is electronics inside the new instruments and electronics and moisture isn´t a good combination.
I suspect that the instruments are not airtight, but close, and that once the air inside is dry, it stays that way. That would mean that silica is a solution.
Drilling would open the inside to the atmosphere, and then condensation is unavoidable because the instrument itself gets warm, while the glass is cold. Any water vapour would choose to settle on the inside of the glass.
