We will work closely with you to figure that out, and you can always have trials. You can always choose one type of interpretation for a certain portion and a different one for the rest. With us there´s more than 1 way of achieving the correct results.
My collaborators require very little oversight. That being said; our process confirms the interpreter’s assistance at different times prior to the start of the event. In the event of an emergency we´ll make sure to have a replacement that meets your needs.
The easiest way is to pay attention to your listeners, people do not fear to be vocal if they are not understanding. One way we always recommend is doing a speedy Q&A session, the best way to know if your message is getting across is by asking what has been understood.