I think it's just about adjusting to fit your own preference - no absolute rules. I tweaked the bass a little on the piezo preset adjustment to good...
Thanks for the reply and yes I had specifically wondered whether CA glue might creep in and fill and seal the gaps. I am not sure there is much of a...
Appreciate the reply & interest. Attaching a small photo here that's hopefully clear enough.
The lightened area where there is a bubble/gap actually...