I have been thinking about this more and I think that going with an HSA-eligible marketplace plan for 2024 and maxing the HSA would accomplish my purposes much better than withdrawing from a Roth to fund a Traditional IRA. I could get the tax deduction on the full amount of the HSA contribution and use some of those funds to pay for health care expenses, correct? I was reading the IRS instructions for Form 8889 and it appears that I can even pay my LTC insurance premiums out of an HSA, which would be helpful.
Correct, with the exception that you can only use them for medical expenses incurred after you establish your HSA. In my state the HSA is established on the date of the first contribution.
If you want to play the typical HSA game, you can contribute, invest the money, incur an eligible expense, then withdraw for the expense much later, after the money has been invested for years and hopefully grown. Put in $1K, have it grow to $2K, withdraw for a $1K expense, and now you have $1K extra that is completely tax free for other medical expenses. (If you need the tax / cash flow, well, this isn't as much of an option.)
LTC insurance premiums are medical expenses for the purposes of an HSA. Note that there are age-based limitations on how much you can deduct - see the information in Schedule A for those limits.
In addition to LTC stuff and ordinary medical stuff, generally OTC stuff also is eligible.
You generally should be able to contribute to an HSA for each month you are covered solely by an HSA-eligible plan. The annual limit is adjusted for inflation each year, but it's somewhere around $4K for single coverage, which is likely in your case since your husband is on Medicare. If/when you're over 55, you can add a $1K catchup contribution as well, for a total of $5K per year.
HSA contributions can also be made any time until tax filing the next year (like IRA contributions). So if you want to dial in your AGI exactly (something I usually do), you can contribute, say, $3K to your HSA during the year, then figure out your taxes in the spring, then make a top-off contribution of $387 or whatever to the HSA for the previous year to get your AGI to an exact dollar figure, assuming you got within $387 in December during your planning phase.