http://www.bowyersedge.com/broadhead.html
Some things Dean doesn't mention:
I use a 10" single-cut bastard file. Get a good one. Grobets are good. Nicholson are common, and work OK, but seem to wear out quicker.
Chalk your file to prevent pinning ... you don't want metal filings in the grooves. Get a file card, and clean 'er out once in a while. You'll be glad you did.
Don't try to make a file last forever. They don't.
This has more application for stout heads that are meant to be resharpened ... remember that many replaceable blades aren't intended to ever be resharpened.
That's why they call them replaceable!
You can use strong two or three blade broadheads with a crossbow too, and I would think that would be especially true with the slower models like the Vixen.
Maybe Bob Stout can comment ... I believe he has used, or uses such heads.