It wasn’t clear on Motiv’s website which adapter was right for our ST’s so I called and they were super helpful. We did a FaceTime call and he had me show him the cap and do some measurements. The adapter we need is the 1108.
https://www.motiveproducts.com/collections/adapters/products/gm-round-3-tab-adapter
https://www.motiveproducts.com/collections/adapters/products/gm-round-3-tab-adapter