Just realized that the multi-cartridge holder for 32-40 does not fit well enough to prevent wobbling when trimming to length. What do you 32-40 shooters use to trim to length??

The wobble is at the case mouth end. I'd have to open up the case base end of the Wilson case holder to move it far enough to tighten up the case mouth end. It's a straight taper and no shoulder to prevent case lengthening, so trimming should eventually be necessary. What process (equipment) is used to hold the case firmly to get an accurate trim.

I have used a Forster trimmer for close to sixty years, and it has served me well. I have and use the Wison also, but found the Forster less expensive to get set up with, especially if you shoot as many standard, non standard, and wildcats as I do. You only need the tool, a collet for each rim size and correct mandrel to fit the neck size. I mounted most portable tools on 1/2 inch aluminum plate that i can mount in a large bench vice for use.

I've used a Lyman case trimmer with universal shell holder for decades. I really like not having to keep changing shell holders for each cartridge I am trimming. 
I spin larger pilots in my drill press and use files or sandpaper to make them the size I need.