Front and rear adjustable spring lengths

[vstibbard]

Hi, hope you guys can help me, I've lost my note book with spring lengths. I’m fitting adjustable platforms to rear shock tubes, from memory the spring length required is 12 inches, pls confirm.
I’m going to run 100lbs rear spring rate I’ll have Khumo185x13 R series tyres on 6” rims all round.
Can someone help me with front spring length please. I’ll be fitting 125-130lbs springs to TTR GAZ shock absorbers and thicker ARB, have not decided but may replicate OEM S2 26R setup.
I’ll run std bumpstops front and Porsche 944 on rear.
It’s for an Elan S2 which will be used for historic road rallies, track days and fast road use, it has a lightweight TTR shell, 1760cc LTC, CR box and quaife LSD 3.77 diff.
Does anyone know rates and length of TTR fast road springs? Or recommendations for a set up.