Router IP address reservation when using an extender

Hi,

I have a Nighthawk R8000 router, and recently added an EX7700 extender, which works really well. I have a couple of questions however.

One of the features of this setup is that the EX7700 extender aliases the MAC addresses of devices connected through it by replacing the first three octets of the device MAC address with those of the router MAC address.

So my first question is how would you configure DHCP IP address reservations in this setup. The device MAC address appears on the router with the first three octets changed, if I reserve the IP address with that MAC address will it prevent the device acquiring it?

The second question relates to reserving an IP address for the EX7700 itself. I noted that if I set a static IP address on the EX7700 and reserved the same one on the router it seemed to work, except I lost connection when the IP lease expired every 24 hrs.

The EX7700 Smart Setup option with a DHCP dynamic IP address seems more stable, I note that the EX7700 defaults to  address 192.168.1.250, I have set this as a reserved address for the device, but is this the right thing to do,  as the EX7700 seems quite happy to wander off and use random other IP addresses?

Dave