The annoying thing of fruitboots is that most come standard with a specific crampon. The Boreal's with Black Diamond, the Asolo with Petzl, the La Sportiva with Grivel...
So if you want to have Petzl crampons on Boreal boots (or any other combi) this is what you can do:
1. Get a couple spacer rings to figure where the bolts need to be.
2. If needed drill holes on the right places through the crampon for the right fit
3. Take the new crampons, marked and well off the boot
4. Weld the spacers in place
5. Tadaaa :)
It works much better then spacer-plates, or loose spacers. It's less weight added and they won't move (like they did apparently when I climbed the Worldcup finals last week, thats why we now got this technique fixed)