I'm wondering at what point we are asked if we want a fully optioned car and if we will be able to see the effect in change of delivery date when we make that call. I might be willing to take a few more options if it gets me a car 1-2 years sooner.
The sequence is:
1) You make a refundable deposit.
2) You'll get an e-mail with "RN" prefix which is like an account number that you include for any further payments from then on.
3) You won't hear anything for a long time. You can check your "My Tesla" web page for any change.
4) People will report that they've gotten an e-mail to configure.
And you will too!
5) You then can click on the link in the e-mail to configure. You can also go to "My Tesla" page to do that too.
6) Once you click to configure, you can click on how many options you want depending on how much you want to pay.
I think you can practice to do that with Model S without logging in your "My Tesla" page to see all the options and pricing.
You cannot do that (that means configuring without logging in) for Model X or Model ≡ currently, because you need an e-mail that unlock your "My Tesla" page.
7) After you are happy with your configuration, you can now "finalize" it and your deposit would be then converted to "non-refundable." That means you've entered a buying contract at that point.
8) Most people won't hear anything for a long time. But if you check your My Tesla page, you'll get a VIN posted there in a few weeks.
9) Then after a few weeks, Tesla would call you to set up a delivery schedule.
And so on...
So let's get back to your question:
a) at what point we are asked if we want a fully optioned car?
No one will ask you.
When you see an e-mail telling you that you can configure now, that's when you can choose barebone, maxed out, or anything in between options yourself.
b) if we will be able to see the effect in change of delivery date when we make that call:
I don't think so. It's been done by faith and been confirmed with past historical reporting. You pay for more options, you'll get it faster than others with less options after factoring in other factors.
c) I might be willing to take a few more options if it gets me a car 1-2 years sooner.
Historically, it is very difficult to predict a delivery date at the start of production because it might be very slow or even stalled for sometimes to iron out some wrinkles.
Once the production is fully ramped up, how many Model ≡ per week, then your Delivery Specialist can give you an educated guess of when you will get yours.
I hope this helps. Good luck.