and Calcium in the proper ratios?

Cymbalta has some usefulness in chronic pain states where the brain overfires and gives faulty responses. As in RSD and fibromyalgia. Cymbalta has some usefulness and it works centrally.

However, having SSRI actions (along with some norepi reuptake), is not a good idea for cramping. People using SSRIs can develop muscle tension and cramps.
This is due to the fact that SSRI drugs reduce dopamine over time. Dopamine agonists are typically used for cramping, and RLS symptoms like you describe.
These drugs are typically Sinemet or Requip or Mirapex. However, they too have side effects and people often don't like them.

The best thing to try is a good absorbable magnesium. Support that with high potassium containing foods, and good absorbable calcium, and leg spasms should improve.

I don't recall what other drugs you are on, but sometimes you get cramping/spasms as a result of nutrient depletions that other drugs cause.
For example: diuretics for blood pressure.

If you try Cymbalta--be advised that it is VERY difficult to come off of. This would be in the 6mos+ time frame. Even the sales reps who sell it and use it ...discuss this negative attribute (at www.cafepharma.com Eli Lilly board). It is similar to Effexor, and that too is hard to come off of, and requires a slow taper and time.