I installed a Forstner 1450 on my Watchco 300. Here are the results on a 7 inch wrist. For folks considering this bracelet, I selected the pre-2021 Forstner Speedmaster end links.
I found sizing and installing the Forstner 1450 to be a breeze.
I like the Forstner 1450 better than the OEM Omega 1171, which based on my prior experience had rattling end links, and a clasp that wouldn't center well. The Forstner 1450 has solid end links, screws instead of pins and a few expanding links to ensure the clamshell clasp won't pop open on humid days when your wrist swells. The 1171 had a habit of popping open on humid days. I was able to center the clasp on the Forstner with no problem.
Back in the 60s, the 300 shipped from Omega on a 1039 or 1116 bracelet (or a black Tropic rubber strap). I think the 1450 is more in keeping with the tool spirit of the watch than the 1039 or 1116. The 1450 gives you the all brushed upside of the toolish 1171, but with greater quality and comfort.
While the polished outer links of the 1039 look great on an elegant Speedy, I thought the same 1039 polished links looked fussy and out of place on the 300. The 300 has a more aggressive and brutish bezel than the Speedy and I think that is why polished links on the 300 look wrong. All brushed is the way to go on the 1963-1969 Seamaster 300 or Watchco. While the 1116 is brushed, the oval interior links rub against your skin. This is the problem Omega encountered when they reissued the 1116 on the 2021 3861 Speedmaster Professional. See videos on YouTube about the 2021 3861 Speedy bracelet scraping skin. In contrast, the 1450 interior links are flat and don't scrape your skin when sliding the watch on an off. (This is also a benefit of the flat link 1039 stylel).
NOTE: Even though the end links look like they have a gap in some of the photos, they really don't. It's just a shadow from the lighting. The Forstner end links look great.
Thoughts?