Velociphile - No longer in the building
1397
1506
Jim, I assume you can't find the (likely) original 1506? If it were my money, for this particular piece, I would go for the 1171 as the 'closest' OTP readily available fit - with stamped end pieces and the vintage rattle aesthetic. It is also a 'light' bracelet with a lot of twist (i.e. comfortable like a Jubilee). Personally I cannot get on with the heavier Speedy style bracelets. However 1171 or others you mention is not as 'flat' a look - but closest.
As for others, you might try to seek out a JB mesh with the horned ends although these are now silly money, they are a clever design and comfy and were used by the astronauts. You might also consider the official hefty 20mm Omega mesh - just don't pay rip off prices for anything - it is quite cheap if you know where to look (not ebay or notorious dealers).
In either case, check your Omega dealer first rather than others as I have known them to turn out cheapest.... It is also easier than people think to find this stuff. good luck.
Velociphile
Speedmaster bracelet
1506
1506 not practical