Oh, I didn't actually realize you were talking about MrC's old scripts. The way those were written way, way back in the day was that they operated based on what files were actually selected inside MC (rather than operating on them via the command line), which means you can't really automate them (not easily anyway, you'd have to script MC to select the files for you, which is dumb). It is possible he modified them to have a mode that takes a file reference at some point, though, as I never used them and didn't follow it closely.
Since you were asking for a batch-oriented Send-To function, and MCAutoQueue is essentially a way to automate the Send-to > External function, I thought you had an external script that would handle being sent the file via the command line.
MCAutoQueue is very general-purpose, but was really built to automate transcoding and other external "processing" (like Comskip) for video files. But, really, it is a way to automatically do the same thing as Send to > External in MC. It will take files, and one-by-one send them to an external script or application, where you can customize the command line arguments, and include any metadata from MC about the current file in the queue (usually but not exclusively the [Filename] field).
So, for this to work, you'd essentially need a script or command line tool that will take a music file somehow (via it's filename, probably), and then do the processing on it specifically.
I'm sure MrC's scripts could be modified to work this way, but if it still works like I remember it working from way-back-when (and it still only acts on which files are actively selected in MC) then that won't work without modification.