User equivalence is user specific, and ssh setup takes into account the user details and the machine finger print. So it does not matter using what ip (rac1, rac2, rac1z or rac2z) you have logged in to the server. If you are logged in as Oracle, then you will be setting the user equivalence for oracle.
However, during installation you need to specify the subnet for rac1 and rac2 as your public subnet
Vandana - Oracle