When we moved to the US, we had to downsize from a 1100 sqft apartment with lots of storage space to what we could fit in 4 suitcases and a liftvan (a wooden box, less than 1/3rd of a 20ft container). This sounds like we could bring a lot, but I assure you it took some major downsizing and weeding out.
We had been living there for 9 years so we had accumulated A LOT of stuff!
The suitcases fit most of the clothes and items we needed the first couple days.
The liftvan, mostly fit my husband's art and a couple small furniture pieces, that I did not want to let go, plus some other things of sentimental value.
We still had to get rid of most our things and that was PAINFUL but at the same time LIBERATING!
The options available here in the US are much better (craigslist, yardsales, donation with tax write off), most of those were not available to us back then.
We gave away A LOT to friends, pretty much each time someone came over, I offered stuff for grabs.
We sold some of the higher end furniture and most of the appliances..
We grouped other items in boxes and offered them for a flat rate as "fleamarket boxes" to resellers for peanuts, but at least they came and picked them up.
We also made sure, each time someone walked through the door to look at an item or purchase something, to let them know, what else we are selling and to ask what else they may be looking for.
Often times I cut deals. Like this young couple who had just bought the Fridge, I offered them a box of China and cutlery for a flat 5 Euro on top of the Fridge deal etc. This made it easier to sell the small stuff and made a lot of people real happy.
The guy who helped his friend carry the washer down the stairs, needed a water kettle, I gave him mine, for helping out his friend etc.
For all my books (that hurt!!) I sorted them in areas of interest. One area was interesting to students at my former university so I put a note on the bulletin board and offered them as a bundle there (for a small pick up fee, because if you offer for free, you'll get 100 calls, but still no one will commit). This took care of about 1/3rd of the book collection. The others went to friends and in the fleamarket boxes.
It took several months to dwindle down all the stuff, but at the end, we only had a very small amount of items that we actually had to toss at the recycling yard (you have to pay for that) and we had a few extra $$ to spend, for stuff we needed when we got here ;)
I would say START NOW!!! Start with the stuff you can get rid of right away and list the things you are still using last!
There are so many options here in the US and it sound you have some awesome stuff to get rid off!!!
I know it's a pain to deal with the listing etc. But once the thing is gone and you have some extra money in your pocket, you'll be so happy you did!
Plus, once you see the first few things go, you start getting on a roll, trust me with this one!!
What annoys me most is we arrived here really light, with not a lot of stuff and somehow have managed to fill up an entire house again!