"a few bucks more" Yea, some even with plates for that, but you get what you pay for. Let me tell you, I went cheap one time on suspension parts. A sway bar for my 75 Corolla. The welded end snapped off in a corner and I looped it through a fence. Very lucky not to roll it. I don't go cheap any more. Too expensive.
Slotting the tower keeps the OEM plate and bearing in tact. I can reasonably trust it for street use.

 

I agree you get what you pay for. I did want coil-overs but most of the better reviewed sets were too costly. I'm making big payments on this car and need to be frugal with upgrades. Thats why I choose the springs route first along with the rear sway bar. When the struts/shock go then I'll go with coil-overs. But for know if I want more camber than what I got (-0.09 on both sides) , I'll dremel the holes a little more. Like you said it's easy enough and you can still use the factory plate which in my case is new.

 

Simple calculatin. The length from the ball joint to the top of the strut looks like about 28 inches. So one degree works out to be just under half an inch the strut top must move per degree of camber. Does this sound right? It has about 3/16 play to start with. another 3/16 grinding the slots sure would not get me to barely a degree if lucky. Not the 1 and a half I am looking for.

For those with real adjustable plated, about how far over is it?