All the best,
Nick

Sorry for the delay, we had to add a new product to our online catalog.
See 15-105 for the pivot shoe and (the newly added) 15-056 for the retainer clip. After you install the hook of the balance into the pivot shoe, snap in the retainer clip to keep the hook from coming out.
If you need to replace your channel balance it will be a custom order (our S785-29 with the stamp option of 2830). There is no top guide on your balance, because the channel balance rests on the screw and bushing located in the middle of the window track. I'll go ahead and email you a purchase link for these balances.
Let me know if you have any further questions.