Depending on what year/model your cluster came from compared to your Brumby you could be in for a real headache like me. From the sounds of it if you don't have the loom with the correct plugs at the back of the 6 gauge cluster you're going to have to either find one or make one from scratch

If you want to find the wiring it needs to be from the same model of car (wagon/sedan), same year with the same accessories or the wiring could be different to what was meant for your cluster. If your ute has single or quad headlights then the wiring you need should be for matching headlights. I'm in a pickle because my 6 gauge wiring was for a NZ model and is completely different to AUS models. So we're making no assumptions, it should be said that the wiring in your bog standard brumby dash WILL NOT plug into the 6 gauge cluster as it is. And depending on the year of your 6 gauge it might have had 2 completely different kinds of fuse box.
Apart from that, oil pressure sender and fuel level sender are different, 4WD lights could be tricky if your 6 gauge cluster doesn't have them (4WD and LO lights) plus if your cluster came from a 4 door the lights for the door open warnings might be different.
Ideally you would need an FSM with the pin outs for your cluster labelled so you can see what you've got. I have 2 of these at home for different years but alas I am not in the country at the moment.