So I talked to the guy at the shop and he reassured me that he wanted me to slot the bottom holes, which I did. It does work, although it doesn't allow much movement on the rear struts before the hub assembly bottoms out against the strut body. It did give enough to get back where it needed to be. It would have worked great if you were going for more negative camber. I actually only needed to elongate the hole about 1/8", it makes a bigger impact on the camber than you would think.
BTW I did it all with a round file, I couldn't find a die grinder bit at my hardware store that would cut it and fit in the hole. Don't try using a rotary file bit, the strut mounts are hardened and it destroyed my bit in seconds. The round file works good though if you get a coarse one and clamp the strut up in a vice or something where you can put some umph into it. Hope this post will help someone in the future.
