Thanks for your photos. Based on what I see here, you have either our S380-27 or S385-27, 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.
You mentioned that your sash is no more than 6 pounds, but I highly recommend getting a precise weight. You never want to estimate when it comes to balance calibration. There is a chart on each balance store page that tells you precisely how much weight each option supports. All you have to do is weigh your sash, regard the chart, and pick accordingly.
Lastly, you mentioned a side clip, but I don't know what that would be. Seeing a photo of it removed and without obstruction would be very helpful. Thank you!