I have the Heat Company system with both the Merino and Polartec liners (they allow the use of touch screens). Have used the system, including the heat inserts in -10 weather.

https://www.theheatcompany.com/en-us/gloves

Measure your hands carefully.

Spent two days with Mike Jackson (bestofthetetons.com) in early spring. (He usually does one day outings.) Well worth it, learned a ton about photo technique and his knowledge about local wildlife and views is phenomenal. His site also has maps and recommendations. Also recommend stopping by the GTNP Visitor Center, they're more than helpful.