File Copy Progress Dialog question about queued file operations and parallel operations

I am still on DOPUS 12.24.4 / Windows 10

In the File Copy Progress Dialog window, can I que up a copy or move large file numbers (queued file operations) so that they run sequentially rather than at the same time (not Parallel operations)? I am aware that multiple copy/move commands will automatically offer to add to the existing Copy queue. By design, I guess Opus only auto-queues when operations are considered compatible. My issue is that sometimes it does not add, but two or more queued file operations run at the same time (with no option to add to sequentially to the first existing que).

When you copy a large batch from say drive C: to D: , then copying further files from C: to D: offers to add to the existing copy que, which is great. But if at the same time I want to copy files from D: to C: , (or basically any other HDD combination) in unattended mode (so I can go to bed), it starts the queued file operations in a new File Copy Progress Dialog, and the two (or more) run simultaneously. Opus treats these as independent transfer directions, and by default assumes they can run concurrently. Yet I often want to be able to merge this with the first copy/move que, but cannot. Is there a way? A way of merging of opposite-direction transfers into a single queue? The problem is that running two or more such queued file operations at the same time, is much slower to than running them sequentially form a single queue.

My AI searches tell me there is a setting in v12 that I cannot find:
Preferences - File Operations - Copying - Copy Progress
“Maximum simultaneous file operations”

I can find "Copy Options" and Progress Indicators" in preferences but nothing about simultaneous operations..

Note that i have turned on the "Automatically manage file copy queues" option. Is that relevant?

Help would be appreciated.

Yes, the Copy command has a QUEUE argument that lets you explicitly add things to a named queue. If something is already in the same queue, it'll wait before starting the next thing. Multiple queues can run in parallel if desired.

The OnGetCopyQueueName scripting event can also be used to change how automatic queuing works.

Thanks for the pointer Leo!
So I made this button, naming a queue, which seems to work.

Copy MOVEWITHSHIFT QUEUE=BedQueue,quiet UNATTENDED=yes WHENEXISTS=keepnewer

BUT I have no idea how to control WHERE the files move to when I use it for the second and third set of file movements? It just adds them to the named queue, as expected, but I don't know where they are going to untill I open that queue and look at the jobs list. I typically have multiple listers open, for my multiple drives, none are dual pane. But this copy command does not seem to offer a destination drive or directory. What am I missing?

The Copy command, unless told otherwise (e.g. with the TO or HERE arguments), will copy the selected items into the destination folder, which is usually the one in the other side of a dual-display window.

In Opus 12, or Opus 13 if Preferences / File Displays / Options / Single display Listers have source/destination modes is on, copies can also happen between two single-display windows.

See Source and Destination [Directory Opus Manual] for a more detailed explanation.

If you want to use Copy & Paste instead, the Clipboard PASTE command can also be told to add things to a copy queue.