An update on finding good, solid 20mm spring bars with 1.2 mm pinions for BN0150 & Co.:
So like many I found out that "harvesting" the original spring bars from the black diver band and using them for wearing NATOs or elastic bands etc. works, but they do make a small clicking noise from time to time, as they move around a bit. I looked around for options, and the best (and actually cheapest, even after having them sent from the US to Germany) I found are these:
(no connection/affiliation with the seller, just a happy costumer).
From the description:
"Item up for sale is a new released custom manufactured with improved design 2.5mm diameter stainless steel FATBAR spring bar with SPHERICAL 1.2mm tip ends available in 3 sizes: 19mm, 20mm & 22mm for your regular size vintage or modern Seiko or Citizen diver watches. We also carry the original Double Shoulder style in our eBay store (eBay item number:381604144143)
These top quality FAT spring bars also features new REINFORCED Double Flange design (please refer to picture 2), unlike those thin flange spring bars, which we often find it damaged by forced removal or improper use of remove tool. This is the best heavy duty FAT spring bars for your Japanese diver watch or any watch takes 1.2mm ends."
They are rock solid and for practical purposes silent. I can make one of them make a noise when pressing on it, but in normal use: perfect. (The original Citizen spring bars would work fine with my elastic strap as well, but every time I took of the Luff Strap and drew it over the wrist (unbuckled) it would click, which annoyed me.)
They are also available with 2.0 mm diameter and 1.2 mm tip: 20mm 22mm Heavy Duty 2.0mm Spring Bar w/ 1.2mm Tip Ends for Seiko Citizen Diver | eBay
So like many I found out that "harvesting" the original spring bars from the black diver band and using them for wearing NATOs or elastic bands etc. works, but they do make a small clicking noise from time to time, as they move around a bit. I looked around for options, and the best (and actually cheapest, even after having them sent from the US to Germany) I found are these:

19mm 20mm 22mm FAT Spring Bar 2.5mm 6309 7002 SKX007 Monster SKX779 Diver Z20Z22 | eBay
Find many great new & used options and get the best deals for 19mm 20mm 22mm FAT Spring Bar 2.5mm 6309 7002 SKX007 Monster SKX779 Diver Z20Z22 at the best online prices at eBay! Free shipping for many products!
www.ebay.com
(no connection/affiliation with the seller, just a happy costumer).
From the description:
"Item up for sale is a new released custom manufactured with improved design 2.5mm diameter stainless steel FATBAR spring bar with SPHERICAL 1.2mm tip ends available in 3 sizes: 19mm, 20mm & 22mm for your regular size vintage or modern Seiko or Citizen diver watches. We also carry the original Double Shoulder style in our eBay store (eBay item number:381604144143)
These top quality FAT spring bars also features new REINFORCED Double Flange design (please refer to picture 2), unlike those thin flange spring bars, which we often find it damaged by forced removal or improper use of remove tool. This is the best heavy duty FAT spring bars for your Japanese diver watch or any watch takes 1.2mm ends."
They are rock solid and for practical purposes silent. I can make one of them make a noise when pressing on it, but in normal use: perfect. (The original Citizen spring bars would work fine with my elastic strap as well, but every time I took of the Luff Strap and drew it over the wrist (unbuckled) it would click, which annoyed me.)
They are also available with 2.0 mm diameter and 1.2 mm tip: 20mm 22mm Heavy Duty 2.0mm Spring Bar w/ 1.2mm Tip Ends for Seiko Citizen Diver | eBay