I know this wasn't asked directly of me, but...
I kind of envision a process where we look at the type of specific government policies/laws that led to harm, then try to assign some sort of reparation for that harm. The policies/laws could be slavery, housing, legal, etc. The reparations could take the form of money, education, preference, funding, etc.
A 'reparations office' could be set up, and the stronger the claim for harm, the greater the reparation. I don't think we can handle 60 million claims, so perhaps if your claim is not strong enough for an individual claim (evidence of a specific act that caused provable harm) claims might be filed in specific 'classes', like 'my family was impacted by school segregation'.
We need a reasonable limit as we don't want to sink the ship while trying to help the passengers.
We could probably do sort of a 'means test', where your reparations decline as your means increase.
I also think we have to accept the fact that any reparations will not make everyone whole again. We can't give what we don't have. I envision this being more than just a gesture, but less than 100% reparations.
I don't want to seem paternalistic, but I think we need to make reparations less in cash, and more in what I would call foundational support. We are trying to fix a long term problem we created and I don't thinks handing a bunch of people a pile of cash will fix a problem in the long term. Foundational support would be more in the form of supporting education, loans, opportunities, etc.
Obviously I've not completely thought this out, nor am I in a position speak for others. These are just my early thoughts on how we might address this issue.