@starkyfubbs
"I used a trade accounting software to generate my Form 8949."
Out of thousands of trades, isn't it true that most of your trades are trades without adjustments?
I hope your Form 8949 preparation software that supports wash sales across several brokers
will partition your Form 8949 reports into two classes,
those with adjustments,
and those without adjustments.
Trades with no adjustments do not require Form 8949 at all and any Form 8949 showing such details does not have to be supplied to the IRS.
"Does it confuse the IRS if I mail "Box D" individual transactions,"
presumably you mean box D transactions with no adjustments.
This is exactly what happens if the tax filer attaches the entire consolidated 1099-B for details. i.e. most of the details are redundant.