So, when I configure this router should I be using the prefix portion of the IPv6 tunnel address from tunnelbroker?
You are supposed to be using both prefixes in the proper places in the configuration.
The screenshot you attached is from a page intended for configuration of 6rd. What tunnelbroker.net provides is 6in4. The two are similar, but not identical. And as you have found out, it is possible to set the 6rd parameters in a way, which for the most part works correctly against a 6in4 provider. If your router has 6in4 support, you'll be better off finding the correct page to configure 6in4 connectivity.
If your router can only handle 6rd, then your configuration is probably close to the best you can do. There are two problems to keep in mind.
The first question is, do you configure the tunnel /64 or the routed /64 for the LAN. Using the routed /64 is more appropriate, because on the tunnel /64 there are a few addresses that are reserved, and nothing on your LAN would know about that. If however you could somehow avoid using those few reserved addresses for anything on your LAN, you really could treat the tunnel /64 as just another routed /64.
There is a theoretical possibility that using your tunnel /64 as if it was a routed /64 could increase the memory usage on the tunnel server. Whether this happens in practice is something, which I don't know.
For both of the mentioned reasons, I'd recommend using the routed /64. That is what this prefix is intended for.
The other problem is whether HE thinks your tunnel is being used or not. HE has been deleting tunnels, which appeared to be unused. One of the methods used to identify tunnels which are unused is by pinging the IPv6 address of the user's router. In your case that would be 2001:470:1f10:632::2. Your router doesn't respond to pings on that IP address. It also didn't respond to those before you changed the prefix.
If your router doesn't have any 6in4 support, the best you can do is to keep using 6rd and hope HE is still able to see your tunnel is in use such that it doesn't get deleted.