Alenco window balance replacements

A quick learner from USA says:
Two window sizes, both use a 28" balance. One balance stamped 2740 BSI LK on the smaller window. The other balance stamped 2790 BSI LG 31 on the larger window. I weighed the larger window sash on the bathroom scale and it was about 25 lbs.

See attached images. I'd like to know what Swisco part numbers I need. Based on the end fittings I'd say I need 395, but I'm confused by the stamp options.
User submitted photos of a window balance.
A quick learner from USA says:
Need 4 window balances plz
Stamp on balance says
32 3 kW cmc 7
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Tom from SWISCO responded:
Thanks for contacting us. I agree, our Series 395 appears to be our best match. The stamp options represent spring strength. In other words, its a code letting you know how much weight your balances can support. The first balance looks like it would correspond to our 2740 option, but you will need to weigh your sash to for the second "2790" option. That is not a standard choice, though one of ours may still work for it.
A quick learner says:
Thanks a lot. That's the one I weighed. 25 pounds.

I appreciate your help.
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Tom from SWISCO responded:
Great! in that case, I'd definitely go with our 2740 option. Two balances with this option can carry 19 through 26 pounds.
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