Separate MQTT Bridge for Solar Assistant and Hildebrand Glow

Hi all,
I currently have Solar Assistant and Hildebrand Glow integrated into HA using the HA MQTT Integration and Bridge addon.
I’d like to look into putting a separate MQTT Bridge up in the middle to control everything.
My thinking is this will give me better flexibility in the future and expand my knowledge and experience with MQTT.
I have spun up a mosquitto instance on a proxmox LXC. I have used it to subscribe to the SA MQTT from the command line and get the expected stream of messages. Now I’m not sure of the best way to set up the .conf to create the required connections, subscriptions, publications to achieve my goal.
Google and youtube have confused me so looking for some guidance as to where I might find an idiots guide to setting up a bridge in these circumstances.
Any help appreciated.