Window 50" x 32.5"
Thanks for your photos. Based on what I see here, you have either our S380-30 or S385-30, depending on the depth of the bottom shoe. That's the only difference between them. I recommend measuring your shoe and referring to our dimensions to confirm the best match.
As for the top sash guide, I think our 18-166 is a good place to start. Like before, you can review our dimensions to verify.
Are those two balances in the same window? If so, someone must have made a mistake at some point in the past during a repair. Two balances in the same window need to be identical.
The good news is that it's easy enough to figure out. All you need to do is remove your sash from the window and place it on a scale to get its weight. Then, refer to the chart you see on the S380-30 store page. That will tell you exactly what stamp option you need beyond any ambiguity. While mistakes are common in this industry, math never lies.
Gotcha, thanks for clarifying. A stamp of 29 3 typically corresponds to our 2930 option. Unfortunately, there is no 2990 option to match your 29 9 stamp. That one is a bit outdated; modern balances tend to be calibrated a little differently. For that window you will definitely need to weigh your sash to verify which modern option works best.