First we gotta get everyone on board.
Believe it or not there are black men against reparations...
I'm not sure everyone needs to be on board or even the majority of blacks need to be on board.
The prior Civil Rights gains were fought for by a minortiy of black folk, from what I imagine, most black folk back then were content/complacent with segregation.
And even a smaller amount of black folk were willing and able to ride for the cause.
Also for reparations to slide through, I think you would need only maybe a 1/3rd of white folk to be with it. Just like back in the day, only a minority of white folk supported black civil rights but it got through.