"the best solution is to make minor adjustments to the downloaded 1099 information to make the totals reported by TT match what's reported as totals on the 1099 correct?"
This is how I used to do it.
make the proceeds come out to match, then adjust the cost of one or more transactions to give you your true gain/loss total.
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Ironically, TurboTax has taken to suppressing the Box A/D transactions with no adjustments.
you won't even be able to see what was rounded and how it was rounded on your filed tax return.
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The correct solution is to use aggregation aka enter a summary.
Regarding stock and options, for Box A and Box D, only wash sales have to be itemized on Form 8949.
The other transactions without adjustments can be aggregated. Report the sub-totals of cost and proceeds for those transactions on Schedule D Line 1a or Line 8a respectively.
If you have no wash sales, there will be no form 8949, No attachment is necessary. No mailing is necessary.
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If you have wash sales, it gets more complicated since those adjusted transactions have to be itemized on Form 8949 and the summary totals adjusted accordingly.
Enter the wash sales on Form 8949, then use the subtotal results on the bottom of that form (Line 2) to know how much to subtract which gives you the Schedule D line 1a totals. Be sure to NOT check the adjustments box in the summary window.
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Alternatively, if entry of Wash Sales is too tedious,
summarize and check the box for adjustments and enter the disallowed amount.
This summary will go on Schedule D Line 1b.
You will be making the mail-in election.
mail the transaction details to the IRS within three business days of IRS accepting your e-Filed tax return.
