I have been trying to figure out how to bend the stays in this direction, and it's not particularly easy. As you discovered, there needs to be a secure way to hold the main triangle from rotating.

As far as bending, I think the gold standard of such things is the Park FFS-2. We used to straighten a lot of bent forks when i was a bike mechanic, the FFS-2 works great. Although I may have used the FFS-1, I don't see the difference.