Crystal balls are usually pretty hazy. My thinking is that for those in the 12% bracket (or the 15% bracket once/if the old brackets come back in 2026 as scheduled) it's pretty much a tossup between Roth and traditional for Mustachians. This is because the 12% bracket allows tax deferred withdrawal between $21,900-51,675 if single and $43,800-103,350 if married, both of which seem like totally reasonable, to downright extravagant spending levels for most mustachians, IMO. And then if you have some of your savings in Roth or taxable you'll be able to save even more without going up a bracket.
If you can qualify for the savers tax credit (which you've figured you can) that might push you towards traditional. If you expect to move to a lower tax state in retirement that might also push you towards traditional.
If you expect tax rates to go up by the time you retire (they're scheduled to go up in 2026 under current law, but not much) then that might push you towards Roth. If ACA subsidies are still around by the time you retire, that's basically another type of tax which might indicate you want more of your spending to come from Roth.
Remember that you'll want at least enough in tax deferred to fill the standard deduction. Since you're clearly comfortable with excel you might try playing around to see the present value (PV) you'll need at retirement to pull out the standard deduction for your expected lifespan, and then find the payment (PMT) you'll need to make into your tax deferred accounts between now and then to reach that balance. You might do the same for the 10% and 12% brackets too. Not perfect, but it will give you some information on the range of balances you might want to target in tax deferred and how much you'll need to put in tax deferred to get there. Adjust as information (like tax law) changes.