[Pills]

My car has xj6 S2 front end. I recently replaced my spax coilovers with QA1, but had custom made springs, as the QA1 springs did not fit.
The guys that did my springs make them to your specs. In order for mine to fit I gave them the internal diameter and external diameter allowances. '
They then dialed in the weight I specified by adjusting the number of coils according to the length of the spring (9 inches in my case) and the gauge of the wire used to make them.
Not real expensive either. Might be worth considering some custom made springs.

PS: I have spare QA1 springs if any one needs them, free to a good home.