Just like "pour[ing] money into the ghettos" won't solve things, I don't think throwing money at descendants solves anything either. It may, however, be a meaningful, well received gesture to many recipients which also can't be discounted. I think in actuality whatever amount would hypothetically be paid would probably be deemed by a lot (maybe most) recipients as not enough and anger people for thinking a nominal sum makes a difference and the people not receiving it would be angry that it was too much, especially those with no ties at all to US slavery in their past. Anything under $10k would be meaningless and insulting and anything over that will surely piss off a ton of people (which you'll probably say doesn't matter, but if it further divides the country and creates more of an us vs them dynamic, it won't help in the long run). Call me a cynic, that's just kind of how I imagine it shaking out.
Looked at one opinion piece that presented this: "Setting the size of the reparations fund can begin with a calculation of today’s value of those long-ago promised 40 acres. The most conservative estimate of the total amount of land that should have been allocated to the 4 million freedmen is 40 million acres. The present value of an overall land grant of that size is approximately $1.5 to $2 trillion. If there are about 35 million black Americans who would be eligible for reparations, this minimum (or baseline) estimate would amount to $40,000 to $60,000 per person." Right or wrong, reparations totaling $1.5-2 trillion would create massive resentment and I think it is counterproductive to the ultimate goal of a world without prejudice and divide.
I think the best thing we can do is continue working to level the playing field for opportunities so that their descendants get the fair an equal treatment their ancestors deserved. I don't think reparations helps accomplish that. I really don't have the answers.