Limiting bandwidth for streaming devices

I am attempting to limit bandwidth for several devices, but the QoS in Sophos UTM is driving me a little nuts. First, let me explain my setup. I have a UTM running 9.410-6. I have a DSL connection on the WAN interface with 4.9Mbit down, 768Kbit up (so pretty crappy in general). On my internal network, I have several streaming devices (Fire Stick, Xbox, Chromecast, etc). At times, we can have up to three streams going at once, and it appears to handle it OK. However, I'd like to limit all of them to a max of 2Mbps EACH. So for every device that starts a download, the most it can attempt to grab is 2Mbps (I'd like to force a lower quality when it sees the less bandwidth). I am using download throttling, and I think I have it setup correctly, but not 100% sure. I was hoping someone could help me with the correct directionality of the packet flow.

• I have enabled QoS on the WAN interface only with 0.7 uplink and 4.9 downlink.
• I have a traffic selector with the following setup:
  Source: Any
  Service: Any
  Destination: Streaming Devices (this is a group that has the IPs of all of the different devices)
• I do not have any Bandwidth Pools on either internal or external
• Under Download Throttling, I have a rule with the following setup:
  Limit (kbit/s): 2048
  Limit: Each destination
  Traffic Selectors: (the selector from above)

Does this appear to be the correct direction, or do I have my traffic selector backwards. It doesn't appear to be working as I watch the maximum bandwidth get used on the dashboard with just one device going. (Not being able to see what device is using that without using iftop through a console is rather annoying and something I wish Sophos UTM could do)

I've been trying to read over every post on this forum that mentions throttling, but none of them have an actual scenario with a single or group of devices (not applications), or actually spell out the configuration.

(On a side note, I just noticed that I had the wrong interface selected for the Download Throttle rules that I created. I had internal instead of external, so that might have something to do with it. Haven't seen any change yet though, so any help on which interface I should be binding these to would be helpful too.