Wheel + Spacer query

[StescoG66]

Car (Alfa Sprint 1.7 Green Cloverleaf) has a tendency to squirm and tramline a bit, not bad but enough to make you keep your wits about you. Tracking now set to parallel as opposed 2mm toe out +/- 1mm. Parallel seems to be the default preference in the owners clubs.

Standard wheels were 5.5J 14" with 39mm offset and 185/60-14 tyres.

I have fitted 6J 15" with 50mm offset but 15mm spacer - therefore net 35mm offset. Tyres are 195/50-15. Not a mega change in the grand scheme of things I don't reckon.

I wonder the spacer may be too wide - just about 3 or 4mm per side. With the 12mm wider rim I think I have put most of the extra width to the outside instead of splitting the difference and allowing a bit more to the inside. Would this make a big difference or am I shouting at the clouds here. Any advice gratefully received (pic for attention )

[GreenV8S]

To answer that you need to work out the king pin offset ie where the extended steering axis intersects the ground relative to the center of the contact patch. They will never align perfectly but in general the closer they are the better.