Full redundancy between the network equipment and the servers

Hello,

For the moment I have a network similar to the image below, the only differences are that both 5224 are connected together through a 4 ports trunk, I have 2 firewall/routers which haven't a redundant connection (both are connected to only one 5224) and to connect to the PCs I'm using Powerconnect 3048 and not 3248.

With my design the redundant connection from the 3048s to the second 5224 is blocked by the STP protocol and so I'm looking for a design to use both connections (primary and redundant) at the same time to increase the bandwith between the 3048s to the 5224s.

My questions are:

1- Can I disconnect the trunk between both 5224?

2- If yes what should be the bridge priority of both 5224?

3- Would the STP protocol still disable one of the redundant connection from the 3048s to the 5224s?

3- Should I create a trunk to connect the 3048s to the 5224s?

4- What would happen to the connections to the firewall/routers?

Thanks for your comments.

Regards,

emmanuel