We recommend only using cyanoacrylate adhesives in liquid or gell form - like super glue, super glue gel, gorilla glue, or other quality cyanoacrylate adhesives. These form a solid and transparent bond between the piezo element and the soundboard, resulting in an accurate representation of your guitar’s sound.
Any soft intermediate layer added between the bridge plate and the piezo element (such as double-sided tape) will reduce the transfer of energy and and usually results in a muted tone with diminished high-end frequencies.