Rear shocks / coilovers

[Perpendicular]

On my 67, I am noticing the rear shocks seem weak. It is lowered somewhat so wonder what others recommend for a rear setup.

Would you do coilovers to help the factory 60 year old springs? If so, what experiences have you had?

If just shocks, what have you seen that works well?

I am starting with the rear as they likely are much older than the front as it was rebuilt at one point.

Thanks for the opinions!