Is there one router only in front of the pfSense and I was not getting it right out how many pfSense boxes will be in that game! Anyway, what you was trying out in the first post will be able to set up since version 2.7.0 of pfSense will be out.
The second thing you should know, is how it works.
Set up a Gateway group
Set up Tier1 and Tier2
Choose a load balancing method between three;
policy based routing
service based routing
session based routing
Set up your load balancing and Gateway rules and marl the WAN interfaces accepting the "class c" IP addresses.
Read slow again, word for word, the last comment from @NogBadTheBad
You still have an overlap unless its a typo.