Multiple nifi instances connected to single nifi registry

[#1]

After following those nice articles, I was able to setup nify + nifi-regristry secured by sharing (copying) the  keystore, nifi.properties and truststore files from nifi to nifi-registry conf directory

• https://community.cloudera.com/t5/Community-Articles/Setting-Up-a-Secure-NiFi-to-Integrate-with-a-Se...
• https://community.cloudera.com/t5/Community-Articles/Setting-Up-a-Secure-Apache-NiFi-Registry/ta-p/2...

Now I need to setup another nifi instance (testing environment) on a different server but connected to the same nifi registry. The idea is to create the flows on testing nifi and then commit and pull from prod.

I generate the keystore and truststore files using the nifi-toolkit I will have other credentials so this nifi instance is not authenticated on nifi registry. 
How can I grant access to the new nifi installation ? Or should I copy the security output to the new nifi server and share the same credentials?

Thanks in advance !

[#2]

Hi Pe, just wondering if you came right with your question. I'm on the same boat and being new to certificates this is rather a deep dig to find the answer.