Window balance

A quick learner from Hollywood, FL says:
Hello, I recently replaced balances for two windows. I have two more that need replacements but the numbers look different. They measure 28 1/2 tip to bottom and the plastic piece is 1" wide. The stamp looks like it is 27905 with a 34 after. The windows are also missing the plastic "caps" that push the balances down but I don't know what part those are since they are missing. Thank you for any help.
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Tom from SWISCO responded:

Thanks for reaching out to us. Can you confirm that you're only measuring the metal channel when determining length? If the metal channel is 28-1/2" then then this will have to be a custom order. Can you also confirm how many balances you needed? You said you needed two more, but I wasn't sure if you meant two more balances or two more windows, which would be four balances.

Finally, it sounds like you also need a top sash guide. Without seeing yours, though, there's no way for me to know what you need. Do you have an identical window in the house that may still have them?

A quick learner from Hollywood, FL says:
Sorry for the very late reply. Two of the balances (one window) are 27 1/2 long (metal channel) and two (another window) are 27 long. I am not sure what the white plastic piece (pictured with a screw) is called but I need 3 of these also. I am also not sure what the metal piece which screws into the window frame (pictured) is called but I need those also. And final same about the large white plastic piece that sits in the window frame. Thank you for your help.
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Tom from SWISCO responded:

Thank you! We can definitely supply this balance for you. I just need one last piece of information, which is the depth of the bottom fitting. I've narrowed it down to 2 options but I can't quite make out the size I need in order to confirm which one to go with. Please refer to the diagram below and let me know which is the better match. Then we can get the ball rolling on a custom order.

As for the other parts you show, they resemble our 16-028 Yale stop and 18-166 top sash guide, respectively. Look them over and let me know what you think.

Comparison of the S351 and S390 balance shoes.
Comparison of the S351 and S390 balance shoes.
A quick learner from Hollywood, FL says:
Hello. Hope you had a happy holiday. The bottom fittings are 1".
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Tom from SWISCO responded:

Hello and happy new year! Thank you so much for the response. I'll email you that purchase link right now for balances made to this configuration. Please note that this will only include the 27.5" long balances, the 27" balances are standard parts and can be added to your cart directly from their store page in our catalog. 

Let me know if you had any questions about this process, or in general, and I'd be happy to answer.

A quick learner from Hollywood, FL says:
Tom, thank you. I think I will start with the 27 in window for now. Which part numbers do I need for the balances?
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Tom from SWISCO responded:

Sure, so that would just be the S351-27, since you said the shoe is only 1" deep.

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