You are usually confined to the insurance limits and the minimum policy in MO for semis is 750k, so they may already know the limit. There are additional claims that can be made (tort claim to the State), but it will be unlikely to get more unless there’s additional coverage which is found (happens pretty commonly) or if you get his employee file and find something bad for the company such as he was working too many hours, had a bad driving record, etc. They can always amend the complaint in federal court if more coverage is found or another claim can be made.