You cannot use Send Throttling for this use case. Why? because:
The system begins processing the email send job at the start time you
specify. The send is not spread evenly between the start and end
times. The system continues sending during the specified time range
until the send is complete or the end time you specified is reached,
whichever comes first. If the end time is reached before the send is
complete, the system will continue the send the next day at the same
start time. This process continues until the send is complete.
The system will continue the send the next day. However, you need it to be sent every friday in a journey..
Your best bet is to segment your audience with a query and place it on an automation that inject those segments every friday ..
Inject all your audience in a Journey and use a combinaison of Random Splits along with waits to throttle the sends on several paths.. However, random splits with low numbers are not very accurate..
Reference: Send Throttle