I got unclear info from the Apple store workers, so I played it safe and went with the base model with upgrade to 16GB RAM only, for $1,200 + $180 RAM = $1,380 out the door, plus the $150 gift card I will use for Final Cut Pro ($200 education package). (they also told me Final Cut Pro is $200 / year which is false, so I didn't really trust what they said).
I still don't have the receipt yet, as I'm waiting to pick up the machine, so I'm not sure how the $150 discount / charge is going to appear, and plus each state calculates tax differently (ie some charge you tax on coupons !) so it's risky.
I have a 2TB T7 Shield that I can use for supplemental storage that is a fraction of what Apple charges. I'll only need it for rare video edits, where the speed shouldn't be an issue.
If you could see your true price at checkout I would have tried adding the storage upgrade too, or bought 2 configs and returned one, but nope. The tax holiday thing is really a weird event and anyway I think if you return a computer you still have to pay for the $150 gift card.