Hi Kyle,
In the Outputs screen, choose your Master rack in the drop-down menu at the top, then patch any required signal (e.g. MixRack Inputs 1-32) to Port B ACE (e.g. Port B ACE 1-32). Then select the Slave rack in the drop-down menu at the top, and patch the ACE channels from the Master to Port B Dante, e.g. ACE 1-32 to Port B Dante 1-32. Patch any Slave input (e.g. MixRack Inputs 1-32) to Port B Dante 33-64.
Hope this helps.
@ddff I think you are assuming they have a Dante card in each rack, but reading the original post this is an ACE-based Dual Rack system with Dante in the Slave rack only.