When you wire a pickup in parallel the character of the sound completely changes, so it's difficult to speculate on what the Abraxas, in particular, might sound like. It's quite an unusual thing to do so I'd be surprised if anyone else has done exactly what you're thinking of, but you might be lucky.
I have a Riff Raff with a series/parallel switch on a single pickup SG, and I like what it does. It gives a brighter, less bassy, less powerful tone, a bit more single-coil like (although it doesn't really sound like a true single-coil). So that's cool, but what I also find really interesting is that it responds differently to the volume and tone controls when you switch between series and parallel, which is fun.
If your guitar's a Strat with a five way switch, why not try wiring it so you can have both series and parallel options?
