Quote from: Neo.op2 on December 28, 2017, 06:05:07 PM

^^ Thanks for the explanation.

Someone please help me with the sizes of different transaction. Assuming 2 inputs and 2 outputs:
Basic - 438 bytes (https://bitcointalk.org/index.php?topic=1782523.0)
P2SH or Pay-to-Script-Hash - Same as P2PKH?
Multisig - ?? (
RETURN - ??
Non-standard - ??

And additionally, how much space if any does Segwit transaction save over the current ~ 438 bytes?

It's impossible to calculate multisig transactions since the size is dependent on the size of the redeem script; the more signatures you can possibly have, the larger your redeem script. Ie, 2-of-3 > 2-of-5.

OP_Return is basically considered as a single output which is limited to 83 bytes. Assuming the transaction is a P2PKH, the maximum size would be the 2input and 1 output + 83 bytes.

Depends. If you're using native P2PWKH, the size would be smaller. P2PWKH-P2SH has a larger size however.