Hi gmdias, here are a few pics of how I hung the rock islands in the tank.
The first pic is of how I glued the fishing line to the rocks. I used the lightest fishing line that I could find which was 2kg about 4.5 lbs breaking strain.I crossed 2 lenghts of the line over the top of the rock and glued it using a waterproof Araldite glue. Which when dry gave me a strand of line coming from the four corners of each rock. and on the 2 larger rocks I glued some mesh to help give the glue some added strength so the line wouldn't pull out of the glue.
I brought a 8mm thick poly carb tile and cut it into 12mm strips which I glued under the hood support which sits on top of the tank. I worked out where I needed the strips and glued them in position with waterproof silicone.
The large triangular shaped rock at the back of tank on the right I glued a heater suction cup and bracket to the back of the rock And use that to keep the rock off glass back of the tank and the fishing line I have siliconed to the back of the tank to support the rock, this way if the suction on the cup releases then the fishing line will hold the rock in place andthe cup will still hold it off the glass.
In the end I ended up gluing the 2 large rocks together using a couple of bits of the poly carb strips. the back of the rocks look a bit messy, If need be I'll cover it with moss to hide it.
The filter power head died on me over a week ago, Have only just received the replacement part today. The tank is now back running with new filter powerhead. and new replacement lightin the hood. So I should finally get the tank fully planted over the next few days, and will post some pics of the tank when it's finished.