Long ago I made 4, 6, and 8 armed versions of Posette. Here is how I did it, as best as I can remember.

Using a text editor I opened a coppy of the "P4 Nude Woman.cr2". In what I call the declaration block, the part between the two "figureResFile" lines, I made a copy of all the arm/hand/finger actors, and after the initial "l" or "r" in the actor name I added the number "2".

Then in what I will call the channels block, the part of the file below the second "figureResFile" line, I made a copy of all the arm/hand/finger actors, and after the initial "l" or "r" in the actor name I added the number "2".

Then in the "figure" block, the part below the channels block, I made a copy of the "addChild" statements for all the arm/hand/finger actors, naming them as in the above examples.

Finally i performed the same copy and rename process for the "weld" statements.

The result is a 4 armed Posette. Obviously you can expand the process to add 6, 8, or as many arms as you want, but it is a lot of work, and as you can see from the pic above the shoulders will probably need some postwork.