Well, that isn't going to work. I could remove the spacers, but then I'd also have to cut off the ends of the screw poles (or buy shorter ones) to make it work and that would be changing the characteristics of the pickup. Plus there's no guaranty it'll fit until I do it and see. I've been looking at other P90 options and they all have the screw poles extending down thru the base plate.
I think my best option here is to deepen the pickup cavity. That would open the door for me to try whatever P90 I want. So now I just have to figure out the best way to do that without a router.