Stock castor is +7.5 degrees with a tolerance of about half a degree. I suspect the SP anti-lift merely corrects any factory drift and gives you +0.5 at the most. If you end up with 8 degrees on both sides after alignment, call it a success at a reasonable price. Equal castor is more important than equal camber.
Offset bushing is not the best method to increase castor anyway. All the SP bushes do is push the rear of the wishbone outboard laterally approx 10mm, which ultimately means the front and rear bush alignment is no longer concentric, but it does kick the strut forward a tiny bit, but nothing like a full degree.
The best way to increase castor is to either tilt the top of the strut further back with adjustable top plates, or move the bottom of the strut forwards with modified knuckles. The SP offset bush method is a half-baked bodge that won't ever give you a full degree of castor.
The SP consoles do improve the front end feel and grip quite a lot, but it's purely down to the wishbone not moving around so much compared to the stock bushes, rather than the claimed castor increase. If there was an appreciable castor increase, wheel hop would reduce, but it doesn't.
