Stream 1 Cadence - change standard options.

Hi, 

I would like to get best practice on changing the timing on an engagement program. If I have 3 pieces of content (emails) in stream 1, where the standard timing is restricted to weekly of monthly, how do I change the cadence to the following in stream 1 which requires the ability to define daily? 

STREAM 1: 

Email 1 - send on Monday   - if send 1 opens, send email 4-in stream 2  / if unopened send email 2
Email 2 - send of Wednesday -  if send 2 opens, send email 4-in stream 2  / if unopened send email 3

Email 3 - send on Friday   if send 3 opens, send email 4-in stream 2  / if unopened consider EXHAUSTED. 

STREAM 2: 

Email 4 

Thank you 

AJA