Vintage Minor Register

I was planning to fit new tyre, shocks and recon springs to the saloon as it tends to wobble about and bounce, plus the springs appear almost flat. I have looked at the table on the forum for springs and removed one of my rears. without loading it seems to be better than my spares but I'm not sure of how we measure the 3.1/8" curvature quoted. From the centre line of the eyes mine measure 3.1/8 to the top of the clamp plate which I assume is more than enough? I am also unclear as to whether despite having enough curve unloaded they can loose their "springiness", ie having them retempered will make any difference?
I look to the combined voice of reason for an answer

Toby, I once had my springs tempered on a Top Hat Austin 7 saloon andn they looked awful. Far too high. Your springs 'look' OK on the New Forest Photo and your measurements look OK also. I would not bother. Highlander.