that doesn't exactly answer my question though.
go to
http://statoshi.info/dashboard/db/memory-pool and set the dates to
from 2017-07-09 @16:00:50.187
to 2017-07-10 @20:20:54.700
this is the most recent period of time (more than a day) with no spam attack and a clean and nearly generic transactions
you can see what i mean when i say in reality it will take only a couple of minutes to fill the 1MB+ block if not already above 1 MB!
The mempool has nothing to do with it. It doesn't matter how many transactions there are, the current segwit2x code has a default block size limit of 750kB and there are no plans to change it. Miners using the default settings will (and did) refuse to mine the required >1MB block, causing the fork chain to freeze completely. The so-called developers do not consider this to be a problem.