Early shackle strap length

I'm trying to build a new transmission crossmember and in order to set it up, I need to fix my pinion angle. The previous owner installed some leaf spring shackles measuring 7" between hole centers.

I ordered new shackles but they probably won't be here for a week. Can anyone tell me what the measurement is either between the shackle strap holes, or between centers of the holes?

Thanks,
Austin