I do not know much about the technical/math involved in SegWit. Just want to clarify: If we activate Segwit, is the blocksize going to be increased to 1.6-2MByte? Or the blocksize will remain as <1MB but having the capacity of equivalent 1.6-2Mb current blocks?
in short.
the main block for people using the native (standard old) keypairs remains at 1mb.
people who AFTER activation and then wait a bit to then get another core release to download can then make segwit keypairs. and move funds over to segwit keys.
once done,
those using segwit keys can then sit their transaction signatures outside of he base block..
so to clarify.
its not depending on activation alone.
its not an instant 1.6-2mb
its actually if only one person makes a segwit keypair tx per block. the base block is still 1mb but the full real data (weight) is 1.000070mb if its just using 1signature
if EVERYONE moved funds to segwit keys. due to the limitation of the 1mb base for the txdata and only the signature sitting outside, and the average leanness of tx's.. only expect ATBEST(100% segwitkey use) 1.6-2.1mb