I tried flipping the pin on one side on my classic Type R to gain some caster. But I noticed once flipped that the pin doesn't want to sit perfectly flush with the control arm, so either I would have to force it flush with tightening the bolts which isn't great or I would need to grind off some material from the pins or possibly make some thin spacers. The pins are not symmetrical in shape so it's not surprising this happened but I haven't read anything about this before. Is this normal or am I doing something wrong?

 

It's normal, albeit a little disconcerting the first time you see it when tightening the bolts. It happens because you're putting a slight twist in the front bush through moving the centreline of the pin/arm. If it's any comfort, I've had my newage like that for 60k miles and the front bushes and ALK bushes are absolutely rock solid with no issues.

 

In this case it's actually the casting of the pin and control arm which gives that gap. It's not much but enough to fit a feeler gauge in there. It was hard to get a picture of it, but clearly visible under the car. I guess there are some tolerances in the castings of the arms and pins. But you can see why the other side of the pin is designed the way it is, it's to give clearance to the control arm. A 2 or 3 mm spacer would have been enough I think, I tried removing some material of the pin but wasn't quite happy and didn't feel like removing any more so put it back in the original direction again. I already have a Whiteline ALK and coilovers with adjustable top mounts so that'll probably be enough for me.

The red line is the angled section of the pin which fouls the control arm and creates a gap.