CUBE HA CLI Questions

[C_Noble]

I'm preparing to setup CUBE HA for the first time and I have a few questions related to the configuration.
I have been using the following Cisco document for reference: Cisco Unified Border Element Configuration Guide Through Cisco IOS XE 17.5 - High Availability on Cisco 4000 Series ISR and Cisco Catalyst 8000 Series Edge Platforms [Cisco Unified Border Element] - Cisco

What does "exclusive" mean in the command: group 1 ip x.x.x.x exclusive

What is the priority and failover threshold command used for?
The command listed in the example configuration is 

Router(config-red-app-grp)#priority 100 failover threshold 75

Is it generally safe to accept the defaults for delay and reload timers?
Is it generally safe to accept the defaults for hello and hold timers?

Thanks in advance!

[b.winter · Accepted solution]

Google is your friend:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/security/m1/sec-m1-cr-book/sec-cr-r2.html#wp3508673721

About the timers:
You can modify them as you like, but I never changed them.