@cmb:
Do you mean that it doesn't matter what monitor IP I use since all of them will be load balanced between my two modems anyway?
No, I'm talking about traffic that gets policy routed, which won't be the case for traffic initiated by the firewall (unless you're getting deep into floating rules, which does give you the flexibility to break your monitor IPs).
Ok. And a pinging a monitor IP is traffic initiated by the firewall? So any IP I use, it doesn't matter because it will come back still load balanced?