I'm mostly concerned about transfer fees.
You can check the quote below. You do not have to worry about the transactions fee, if you send to the 20 addresses one by one, it will cost you more fee. Although, sending to the 20 addresses will also cost you more fee but in a way that is far lesser than sending to 20 address one by by. What matters is the size or weight (segwit) the trandaction and not the total amount that you are sending.
Sending 20 single transactions with 1 input / 1 output each, costs 3-4 times more than sending a single transaction with 1 input / 20 outputs.
If you play with the
site linked by Lucius:
1 input / 1 output:
~138 vbytes 20x 1 input / 1 output:
~2760 vbytes1 input / 20 outputs:
~784 vbytes What matters is the size of the transaction, not the actual amount been sent.
Correct.
And the size is determined by the amount of inputs/outputs and the address type (are you using legacy, multisig, segwit, ..).