I was off work today so fiddled with this some more.
After marking out the pickup cutouts more accurately with some pickup surrounds I cut them out. I've get much better at cutting things with the Dremel, as per usual you work out the best way of doing something just as you come to the end of the job.
I used a sander mandrel to shape the lower edge of the scratchplate quite a bit and made the point at the lower horn much more aggressive.
Drilling the holes was a bit hit and miss, I clamped the plate to the guitar then poked a pen through the holes from the back but it seemed to still move about so this took a few goes. I used a Stanley knife to scrape a bevel along the edge of the plate as the last step.
The second photo is it all back together with the plate stuck to the guitar body with double sided tape. In the end I had drilled the bridge pickup mounting holes too far back and had to make them oval for it to work.
More of an issue is that the neck pickup is slightly too far toward the bass strings, it'll work but realistically I'm going to have to make a second scratchplate to correct this. You can't really see this in the photo because of parallax but it's obvious when you look at the guitar.
Anyway, I'm happy with this as a proof of concept. It does the faux strat thing well and may make people do a double-take. Which was the whole idea.
Tomorrow I'll wire this back up and use it for a bit before tackling the next iteration of my project.