What leaf springs?? Experts please chime in

To solve for rake, you can just get yours re-arched.
For a little more performance you could add a second mainleaf, from under the front eye to under or near to under, the rear eye.
Adding rake at the back,also subtracts caster at the front. Losing caster gives up high speed stability.
Adding rake at the back,shifts weight to the front. If the front ride height changes, the camber may also change.
if the camber changes, so will the tow-in.

Sometimes after raising the back,the car wanders at hiway speed. A new alignment may/will probably, be required.