In the absence of a specialist manager administratively and technically together for managing the project. Which is better his presence alone? And why?

When a specialist Manager administratively and Technically together is not avaiable try to get maximum details on project from the customer so that person can understand what are customers expectations.

Follow a process like listing out - tasks, deadline, priority of tasks, use of google and other tools to find technical help and use of other members who can help and contribute.

all put together a person can achieve85% if not100% as process is followed throughly.

Please explain your question for our better understanding, if possible.