My advice to you would be to scour the new inventory options to see if you can get something before year's end. Firstly, because you may lose out on the $7500 federal tax rebate, and secondly, because you will get your car a lot faster. You can either search for inventory vehicles at
Tesla Inventory Search or reach out to someone at any Tesla store that can give you whatever options are available. I will warn you that there generally aren't too many options to choose from in the 75D and when there are, they are gone fast.
Hope this can help you out