routing different subnets

Hi

My current setup is very simple and straightforward

A 64.XX.XX.49/30 connecting my switch with my provider’s network and  I have a couple of /24 public ips in differents /29 vlans on the switch

The switch ip is 64.XX.XX.50 and the default root is 0.0.0.0/0 64.XX.XX.49

 Now I want to set a Sophos 330 in the middle

I want to use routed instead of bridged because I read about the bridge limitations and I want to add HA in the future

 What I’m planning to do is:

 In the Firewall:

• Set 64.XX.XX.50/30 in the  WAN interface with gateway 64.XX.XX.49
• Create a /30 let’s say 172.XX.XX.129/30 in the DMZ port

In the switch

• Delete 64.XX.XX.50/30
• Set 172.XX.XX.130/30 GATEWAY 172.XX.XX.129
• Change default route to 0.0.0.0/0 172.XX.XX.129

 Am I missing something?

Should I create static routes for my /24 classes?