The examples you were given will work but I would say not very reliable. If you have ANY blips in the object you are monitoring, it will flop over. It would have been better if they allowed it to track more than one object like the ASR IOS code does.
sla monitor 1 type echo protocol ipIcmpEcho 188.8.131.52 interface outside-SpectraNet frequency 30 sla monitor schedule 1 life forever start-time now
sla monitor 2 type echo protocol ipIcmpEcho 184.108.40.206 interface outside-SpectraNet frequency 30 sla monitor schedule 2 life forever start-time now
track 123 rtr 1 reachability delay down 30
track 234 rtr 2 reachability delay down 30
track 456 list threshold weight object 123 weight 5 object 234 weight 5 threshold weight up 5