You would like to think the MX supported /31's, IPv6, IKEv2, etc - but alas no to all of these (at least not right now).
If you work for an ISP, I would suggest you consider using DHCP allocation - because then you can give out /32's - and have even less wastage. The Meraki can handle being given a /32 via DHCP (as can pretty much every other piece of CPE).
Assuming all of your clients get presented at layer 2, and you are using a Cisco IOS-XE router, then you can use something like the below. Note that 10.1.1.x would be your public address space, and that this makes the DHCP allocation static based on the VLAN it is coming in on (rather than the normal MAC address).
So - make the jump to /32 allocations and save even more address space!
ip dhcp use subscriber-id client-id
ip dhcp subscriber-id interface-name
!
ip dhcp pool dhcppool
network 10.1.1.0 255.255.255.0
default-router 10.1.1.254
update arp
address 10.1.1.30 client-id "Gi0/0/0.30" ascii
address 10.1.1.40 client-id "Gi0/0/0.40" ascii
!
interface Loopback0
ip address 10.1.1.254 255.255.255.0
!
interface GigabitEthernet0/0/0.30
encapsulation dot1Q 30
ip unnumbered Loopback0
no ip proxy-arp
ip verify unicast source reachable-via rx allow-self-ping
!
interface GigabitEthernet0/0/0.40
encapsulation dot1Q 40
ip unnumbered Loopback0
no ip proxy-arp
ip verify unicast source reachable-via rx allow-self-ping
