Tesla can avoid or soften the "Model 3's in transit on the ocean at the end of the quarter" problem in Q1 by ordering their production smartly: by making European/Chinese Model 3's in January and February, and switching back to producing mostly for the American market in March.
This gives ships started in January and February enough time to deliver the cars, as transit time to Europe and China is only 20-25 days.
In April (first month of Q2) they'll switch back to making EU and China versions again. They'll be able to do this as long as the new order queue allows a 2:1 allocation of deliveries - which should be possible in Q1 and maybe Q2 as well.
Tesla could also "ramp up" their in-transit inventory to soften the effect, by slowing EU/China shipments in Q1 but not entirely stopping them. This way they could distribute the transit inventory buildup to over 2-3 quarters.
I.e. Tesla has a number of tools to manage the "vehicles in transit" inventory effect in Q1.
The current VIN allocation patterns support this view: earlier Q1 VIN allocations were mostly international, but the very latest batch was U.S. mostly:
BTW., let me attempt an early quarter VIN estimate: if we apply the simple "85%" rule to the VINs already allocated in Q1, and assume that the rest of the quarter will allocate new VINs like in Q4, then
projected Q1 Model 3 production output is approximately 72k units currently, or an about 15% increase over Q4 levels.
"Carsonight" (reliable source who is regularly talking to Gigafactory workers) also reported that there were no line worker layoffs at the Gigafactory, and that they are making 6k/week Model 3 battery packs sustained, and are hiring. They are also building a new Grohmann battery model assembly line at GF1, which Carsonight guesses might be the assembly line for the new, lighter, cheaper Standard Range battery pack.
~6k/week battery packs project ~78k Model 3 production in Q1, a +25% increase over Q4.
So I think Q1 and Q2 could easily be new record quarters in every metric (especially considering that Tesla Energy is ramping up again as well), but it's more complex logistically than Q3 or Q4 was, so it's prudent for Elon to be cautious about expectations.
Finally, the removal of the 75 kWh pack and the reduction in Model S/X production is consistent with the introduction of a new 105-115 kWh battery pack: annual 18,650 output is limited to about 8 GWh, which is a reduction from 100k Units to 70k-80k units. If at the same time they increase prices of the new Performance, they'll maintain or maybe even increase S/X cash generation with little effect on revenue.