I never owned a .33-47, but I think that what you will probably find the best is to use a .32-40 sizer, working it a bit at a time, until you get the taper down enough to chamber. Then, maybe the expander from the .338 mag may work, or just fireform like you did with plain .32-40 cases. Good luck.

Ditto to what Vall said.  When I got my first 32-40 high wall factory brass for it was unobtanium, but Winchester had recently made a run of their (short) brass in 38-55.  I knew nothing about annealing brass back then, so I just took an RCBS FL sizing die and with some Imperial sizing die wax, sized it stepwise in about 3 steps, to 32-40.  I put a couple of grease dents in a few cases from too much wax or too large a sizing step, but they blew out in my fire forming with my first trial loads. 
I once had a high wall barrel that Siegrist had opened up to .338.  I just used 32-40 brass and breech seated and it did fine.  Then I foolishly sold that rifle.   
Froggie

I use my Lyman M die expanders for a lot of case forming. I have dozens of different expanders I bought all at once from a guy at our gun show. They came with a wood block that holds them, and two die bodies that are short and long. Both die bodies have the sides milled open to make a viewing window so you can see the expander enter the case necks.
I can expand necks to the size I want, or form brass down first, and then expand necks back out. Makes it easier when fire forming to blow cases out to fit the chambers.

Thanks, everyone. It'll be awhile before I get to it, but it seems like the .32-40 dies I have will accomplish the mission. I'll report back when I try it. I will mention that in my experience when reforming .30-30 brass to make 8.15 x 46 R, Imperial Sizing Wax took WAY more effort than RCBS lube on the pad-which was easy as pie.

I've been careful to follow the admonition to not use too much Imperial Sizing Wax. Is it possible I haven't used enough?