Four to six weeks from the first to the last of the first batch Pandoras. Give or take a couple weeks for testing and tweaking the assembly process.
Once the manufacturing process is 100% nailed down (2nd batch onwards) the plant can make ~5000 per month, though they can only make them as fast as we can get parts. Second batch will probably start up about two months after the first is finished (again, depending on parts availability).
So at least 3-4 weeks before first batch starts, 4-6 weeks after that it finishes, then ~8 weeks until the 2nd batch starts. If you want a Pandora soon, order from the first batch. Otherwise you’ll be waiting a while.