Hellzero

This doesn't look like carbon at all, but the more classic plywood or MDF... Carbon dust ist not really white. I know it's written AeroTech on it, which is even more weird.

Don't forget to link each copper shielding to ground otherwise it will be useless. And it's really very often forgotten. So solder a wire between the two cavities and a wire from the main one to the grounded pot. Use star grounding for optimal results.

This must be one of your early attempt then...

Are you a designer ?

Weirdly, the all time award winning ugliest bass ever has not been shown. Now it even comes in a colour fitting the shape... When designers have sh*t in their brain, this is what happens. How wrong can a design be ? Check the photo above...

@BillyBass You forgot one very important point : 4) Go to a real luthier who is also a bass player (there are some) and get your bass totally set up to your taste while staying there when he is doing the work. And don't forget that the strings have also a great impact on the sound. Come with your amp too. You have excellent pickups on your bass, so the "issue" certainly is the perfect setup. Sometimes it takes me 2 to 3 hours to have a perfect setup on a bass and I've set up thousands...

A fretted Fender Tony Franklin signature model will also be perfect just like any very good sounding P-Bass with an added Jazz Bass pickup in the bridge position, which is a typical 80's mod. Avoid the expensive Yamaha BB2024X that sound really dull, especially compared to an old Yamaha TRB-4P...

An old Yamaha TRB-4P will tick all the boxes.

According to WD Music, this one is exactly the same : https://www.wdmusic.com/wd-custom-pickguard-for-fender-american-deluxe-21-fret-jazz-bass-details.html

Here is your answer. So you'll spare some money for a physiotherapist or an osteopath. 😉

Does it justify the delirious asking price ?

You can also do it the Fender way and spray the frets too. Then make a frets dressing... They made it this way at least during 4 decades without anyone ever complaining.

Sorry @Happy Jack it's tuned in D.

This was recorded with a cheaper than chips amp through my smartphone... Le Fay Remington Steele 6 RHT CC CAP Big Block.mp4 This is the amp : https://m.thomann.de/gb/joyo_ma_10b_portable_bass_amp.htm Strangely, it sounds amazing at, of course, low level. I also bought this to use if off the mains, but it can also work on batteries : https://m.thomann.de/gb/harley_benton_powerplant_powerbank.htm

This :

I found it next to your toilet, or was it in the Bongo case...

Even better...

Send me back my money !

Storing is one thing, you have plenty of more or less coherent explanations on how to do it the safest way. If your storing place is dry and the instrument is not subject to any fast temperature and humidity changes, than it will be safe. The problem you don't mention is getting them back into your renovated house. I read that you'll have to make some plastering which means water and maybe a lot of water (you'll be amazed by the huge quantity you'll use). If you get your instruments back into the house with a permanent high humidity, get ready for some huge problems. Buy a hygrometer for your storage place and one for your house as a good storage humidity rate is around 45 to 55 %. And please store your instruments tuned with the correct tension on the trussrod as it's wood and it's the way it's intended to be used or get ready for some twisted necks and scratchy pots... Another solution is simply to sell your gear and buy something "new" when the renovation is over as you wrote that they are not high value instruments.

And the 6 strings model has 7 strings too. Glue, definitely !

I should have kept mine...

I'm no tiger, I'm a lion.