for now 2MB will do the trick for the expand faction without wiping out miner fees significantly and get us there, only this route leads to a fork.
(We can call this period the excess profit period where on top of block rewards high txt fees exist and with 300,000 Transactions in the mempool that is not going to change for a while yet and is the opportunity of a lifetime if we do fork all new chains will retain the Bitcoins owned today.)