It is pretty simple. From a claims adjuster and auto insurance perspective, the total repair costs, plus loss of use during the repairs have to be more expensive than the fair market value of the vehicle minus the salvage value. It really comes down to dollars and cents.
If you really want the car to be a TLV, tell the adjuster that right up front. Then help supply documentation to make it easier for the adjuster to make that decision and sell it to his superiors. I would get a repair estimate from a good shop (to negotiate down from), and I would also try to the local Tesla Service Center to weigh in on the expense and difficulty of the repairs due to the structural damage. Perhaps the SC might think that it is impossible to economically repair the car.
I would then try to get some information about the salvage value of the Tesla (which might be pretty high if the battery pack is intact). You want the salvage value to be high.
You also want to gather evidence about the fair-market value of your Model S before the accident. How old was it and how many miles are on it? You want to look for comparable sales if possible, trying to find the lowest ones possible.