That's not so much going to be an issue in this case. But a lot of the time, especially in federal white collar cases, the defendant isn't in custody during sentencing anyways.

So in this case is SBF still in custody awaiting sentencing?

I believe so, because he was an idiot during the trial and violated his home confinement conditions.

But his sentence is going to be so long that there isn't going to be any injustice at play for him to be in confinement for a few months while they work the numbers out. He's not getting out in a year or two.

Yes. He was out on bail, but that was revoked for witness tampering ahead of the trial.

I doubt he'll get out before sentencing, he's looking at up to life in prison so in addition to having a demonstrated history of ignoring his release conditions he'll also be a huge flight risk.