Please understand that I was not highlighting the size of this movement just to be cruel or a downer.
A critical mass of participation is necessary for something on this scale to work. If this gets buy-in from only a few tens of thousands of people, they are just going to be harming themselves by participating on 3/15, rather than effecting any real change. It's not feasible to set a date eight weeks out without first having specific demands in mind or some kind of broader organization.
I have to echo other commenters who are boosting https://generalstrikeus.com/ (which you have thankfully also reposted to this community.) For this kind of mass social action unity is really important, and it makes sense to back a movement that already has greater support instead of fracturing the landscape by starting a new one. You can think of it like the spoiler effect in US politics.