This could have gone in the watchmaking forum, but I think it's equally appropriate here. I have an Omega 283 which I just serviced and is running fabulously. I replaced the mainspring because it was set. Bestfit claims the correct White Alloy spring is the 68-N which is 1.5 x .14 x 13.5. Ranfft archives lists a spring with .125 and cousins lists a spring with .135 strength.
The reason I ask is because the ticking is loud and driving me nuts. This indicates to me the spring may be too strong. The watch is gaining only 1-2 seconds/day, but I don't have my timing machine so can't measure amplitude. I'm guessing it's a little over 300 and it's not knocking. I use the 68-N in the 30T2, but it has a lower jewel count so I'm guessing it needs a stronger spring. The 283 is a common caliber; maybe someone can tell me what spring they have had the best experience with or know what is correct. I don't have the original manufacturer sources for this. Thanks a bunch.