Gre source interface question

[ColForbin]

I have router a with a gre tunnel (tunn 1)to router b. Gig 0/0/0 to Gig 0/0/0

i need to make another tunnel from A to a third on router C. C is connected to B on gig 0/0/1. 

No routing protocols it’s a small network all static’s. 

What’s the best way to handle the source interface on router A?  Use the public IP?  The interface itself, gig 0/0/0? Or the Tunn 1 IP addr?

[MHM Cisco World]

Tunnel IP use as source of tunnel that can not be 

Use IP as source or egress interface 

Sure egress interface' this make your tunnel down when source interface is down.

Can I use same interface as source interface of two different tunnel points to two different remote peer ? YES sure you can 

MHM