I may be making a charitable donation this year (2021) to my school; it will be about 1.5 times my AGI.
What is the most tax-advantageous way to make this donation? If I make the donation in stock with a long-term capital gain, will it wipe out my income tax liability for 2021 to 100% of taxable income in addition to wiping out the capital gain tax liability? Or will it wipe out income tax liability only to 30% of AGI?
Second, is there a limit on how much of the unused charitable deduction I can carryforward to 2022? Will it flip back to 50% of AGI for cash or 30% of AGI for stock?
Finally, are there any hidden reefs or shoals I should look out for? As one example, if I make this donation, obviously I will make zero (or at most greatly reduced) quarterly estimated payments, but the gift will not be made until after the first quarterly payment is due, and possibly not until the second quarterly estimated payment is due. Will this cause interest to be assessed on the "missed" quarterly payment(s)? Anything else to worry about? (Please don't give advice on donor advised funds or other money management. This is purely an income tax question. Thanks.)
(Addition in response to comment: The Standard deduction is not relevant in this case.)