Just so we're on the same page with the geometry, your tyres are fouling the top of the arch, where they normally rust? I think you said in a different thread you need less castor because the tyres are also hitting the front of the arch, next to the bumper?
More negative camber will tuck the top of the wheel inboard, and less castor will push the wheel more towards the driver. You can't run less than OEM Castor (+7.4) though because the angle is set into the suspension tower. You'd need a method to pull the wheel back from underneath.
Sounds like you need a bit of both! What width are the 19s? Any spacers? Even the OEM 18s are borderline when driving hard on bumpy corners so you must be on the struggle bus with those beasts!
Yeah I was told the same with my Ohlins coilovers but standard coilover springs from the Eibach shop fit just fine. I think they're a German metric version of regular 2.5" ID springs, so 60mm or something daft. The Ohlins only have +/- 15mm of adjustment either side of their standard 20mm drop, so I had nowhere near enough threads to use the Ground controls. I don't like helper springs and I never got around to ordering longer springs, so I just gave up on the idea!
I would like to revisit them at some point as there's more to solid top mounts than angle adjustments. Way better steering feel and damping for starters.
Anyway, as for you issue, maybe some pics would help? Shame you're not round the corner otherwise I'd pop round and assess the situation!