Some things are a little different than your tank, but here is what I just did upgrading my 155 to a 180, it's also the same method I used when I upgraded the 50 to the 155:
I put most of my important corals in a QT tank, this time I used my display refugium, but in the past, I've put them in rubbermaid containers with a light, heater and powerhead. I then moved rock into the new tank. I moved half the tank one day, half the tank the next. Each time that I moved rock, I added Prime to keep the stress level down on the fish, and dud a large (30+g) water change after about an hour or so. Added extra carbon to the 155 and tested parameters 3x a day and kept extra water on hand as well as Amquel and Prime. On day 2 of adding rocks to the 180, I added bagged "live" sand. I then took 6-8 cups of live sand from my 155 and seeded the lice sand in the 180. Prime and water changeon 155 because sand kicks up a lot of cr@p. Dat 3: move coral. Day 4: test both tanks, move fish. It took about 8-10 hours to get all fish moved. When stuff really started to get kicked up, I started putting the fish in buckets with airstones and/or powerheads. After all the fish were out, I fished out the rest of the nassarius snails that were hiding in the sand.
Fish and corals have all been in the tank since Wednesday/Thursday of last week. Everything is doing well. We only lost 1 fish, my mystery wrasse, he jumped out. The corals and fish all look great and are enjoying the new tank. We are still keeping extra water on hand and have been running extra carbon in the 180. I think having the refugium definitely helps. Now I just have to wait out the diatom bloom caused by the bagged sand.
For you with the craved coral, I don't recommend seeding. I'd start with all new in the new tank because it traps a lot more than sand does. Just keep lots of extra water on hand, run more carbon than usual, and have Prime/Amquel on hand.