The good news is that on the LSL, you'll be riding in the new Viewliner II cars. Hopefully, the heating/cooling 'bugs', if any, will have been solved by December.
In my opinion, the Viewliner I cars were the ONLY equipment where the temperature control worked and it usually was comfortable in my roomettes within 30 minutes or less. Having 4 different airflow outlets helps in getting/keeping control.
In Superliners, the room temperature control is more decoration than functional. As I understand it, there's a master control in one of the locked downstairs cabinets that apparently have a heat/off/cool setting and 'low/medium/high' range setting.
However, Amfleet I and, to some degree, Acelas, have similar settings but their 'function' settings are: blast furnace/off/arctic winter. I've ridden the NEC extensively in the past 20 years and in the summer, experienced passengers always wear something with long sleeves, usually an easily-removed outer layer. I opt for a wind breaker style jacket. In the winter, it's just the opposite. Ones' overcoat and sweater are soon removed.