Brake System-69 Cuda

Couple questions hoping to get answers to. I have done the standard swap from drums to disc on the front and 8 3/4 out back. I notice in the service manual a metering valve in conjuction with the t-splitter on the rear end and proportioning valve up front.
Do I need this metering valve?
Will the e-brake cable assembly from a wider 8 3/4 rear (69 e body)work with standard A-body width?

Thanks for your help.