Hey Jordon. Since both nylon attachments lack 'wings', or side tabs, and since you're saying the shoe depth is greater than 1", I believe this is an S390-10. Double-check the shoe depth to be safe. The shoe on the Series 390 is 1-1/8" deep--but these shoes can wear down a bit from age, so a 1-3/32" measurement wouldn't be too unusual. So long as it's more than 1", it has to be the Series 390 given this configuration.
For a stamp option, choose 0930. Let me know if you have further questions.
It's uncommon for a balance whose stamp reads "0930" to have a 9" long metal channel. However if you're confident that that's accurate then you should go with the 9" version of this balance instead. Note that you will need to weigh your sash on a scale to determine the proper stamp option for this size, since it's calibrated differently.
We can supply the 9" long S390 balances calibrated to support a 16-pound sash but it will need to be a custom order. We just sent over an order link and price quote for the balances you requested. Take a look and let us know if you need anything else. Thank you!
