The documentation seems to say that bridge mode or router mode applies to how data flows between switch groups, am I correct?
As I see it, you need to start thinking that CRS is a switch plus a single port (switch1-cpu) routerboard all in a single box. The way to set this up is different from any other non-CRS device, even if you can still do things "the old way" using the CPU of the routerboard. CRS has a switch chip and if you want wirespeed you have to set things up on it.
If I don't need to do any trunking or routing, I don't really want to use bridge mode, nor router mode. I really just want one switch group. Correct?
If I do want to create a multi-port link, aka trunk group, then that group of ports would be a separate switch group with a different master port than the rest. I would then have to bridge these two master ports together, and as this involves the CRS CPU, three would be a negative performance impact.
You can set up a static trunk in the switch chip directly, even if the ports have the same master-port as other ports:
/interface ethernet switch trunk
add name=trunk1 member-ports=ether6,ether7,ether8
Check the example in the wiki for hints on how to set up the other side of the trunk.
As there is no bridge, theres no CPU involved, so you get max speed the switch chip is able to give you, aka wirespeed.
I verified my CRS226 has a bridge1, and there is a checkbox it is the root bridge. But since I have port 1 as the master port, and all 23 others, plus both SFP+ slots as slaves of port1, I don't think I have anything going through the bridge, other than management traffic, so I don't have any non wirespeed port to port?
I think that you should remove the bridge, because bridge configuration may have preference over the switch-chip settings.