The C5 (and G2 WAN) should have options for DHCP with a persistent Static IP. Then, when the C5 picks up a DHCP address, the old static remains and can still be used to communicate with the C5.
This is what I picture as an example:
* A5 blocks all 192.168.1.0/24 traffic (preventing access to other C5 radios in the fallback range on the network)
* C5 has 192.168.1.20 always (including after receiving a DHCP address)
* G2 has 192.168.1.2 always (including after receiving a DHCP address)
Then, I show up at an installation, plug in a prepared G2 and a C5 (both expecting DHCP addresses). I can connect via WiFi to the G2, navigate to 192.168.1.20, and it will ALWAYS get me to the C5 radio. Then, I log in and aim accordingly. During the process, both devices pickup DHCP addresses, but the aiming process continues because the static is persistent and not just a fall back.
A secondary suggestion: Have a second static on the C5 (i.e., 192.168.1.21) that goes straight to an aiming page with a display, graph, and beeping feature, and does not require any login... just shows the signal strength and maybe a couple other parameters. This would be very efficient.
Example with another vendor: Cambium uses 169.254.1.1 for a persistent IP on the ePMP series. Plug a laptop straight into it, and it will fail to get an IP and fall back to a 169.254.x.x address. You can always get to the ePMP radio just using 169.254.1.1 and a laptop will effectively auto-configure to talk to that address. By default, however, you might not always connect to the closest radio since they all respond.
The easier an installation is, the less it costs.