Ballast Tension

With 167 pages of discussion and no "search" function, I'm going to take a chance on double posting here. I hope no one minds.

I'm looking to replace ballasts that I suspect may have been mistakenly installed at the factory. I assume that the "stamp" options pertain to spring tension. Is this correct, and is it possible that ballast displacement/failure could be remedied by a "step up" in tension, particularly if they were wrongly installed in the first place? Would this involve simply choosing whatever stamp number is higher and available among the choices given on the part order page?

I understand that too much tension makes the window difficult to close, but I'm sure one step up won't be too much. Plus, the possibility of spending $25 as opposed to $250 to have working windows seems worth it.

Is there any other hardware option that might help keep them in place?

Thank you for your assistance.

Photos per request: Stamp is 2420.

25" is correct. I had guessed series 390 with the 15-001, because it's shoe looked to have more similarly rounded bottom-front corners. However, now that I measure, the 15-001 doesn't seem right, either. The 15-003 bottom dimension of 1 3/16" looks right, but it doesn't give the front slope. It looks like mine is 1 1/8". I'm glad I asked before ordering.

I am quite sure that it isn't the 15-002, since the bottom dimension of mine is 1 3/16", while that of the 15-002 is 1", according to the illustration. Sorry for not being clear. I think I see why you were confused.

Thank you for the additional info on the 15-003. It definitely looks like the one I need, the only problem being that the ballasts that use this shoe(series 710) don't use the top I need.

Thank you for your help. Actually the main purpose of my initial query was to determine whether an increase in tension would be appropriate, and more specifically, if it might help prevent displacement/dislodging, as these have undergone, thus necessitating their replacement. I also mentioned suspecting mistaken installation at the factory, but I checked one of the other windows and it has the same ballast. Is there still any reason to try a different tension (assuming that the 4 digit stamp correlates)?