If its been cleared, I don't really see a reason to strip it either. Depends on how poorly that base was sprayed, and wonder if there is going to be an issue with the bond of the clearcoat to it. But no reason you couldn't otherwise sand the clear smooth, shoot some epoxy on any cutthroughs you have, and reshoot base on top.
Sounds like you already bought the paint, but you may want to go with a better line and a polyester based basecoat. I haven't used nason, but heard others say many times on here how the metallic control in nason is not the best, and how tricky it can be to spray. I have used the nason clearcoat a few times, and didn't think that is too bad, layed down well for me anyways. But the 496 unless you use slow reducer and activator will set up aweful quick. I remember having a bear of a time shooting some metallics in omni many many years ago, when I was still fairly new to painting, as well as many colors that coverage was pitiful.This is just another area where using a better base usually pays off, coverage and ease of use.
I would surely practice some more before respraying the car to figure out what your doing wrong. Get you gun dialed in and if it ends up being needed, how to shoot a mist coat to help even a metallic. But you still will need to be able to get the base down medium wet, and shoot your mist coat soon after while the previously sprayed stuff will still accept it, or else you could again end up with a dry, rough or cobby base, and possible adhesion problems in the future between the base and clearcoat.
I don't know if you have to use different product then other areas being in california, but seems to me, the more they change the voc laws and make them conform to tougher standards, the crappier the product becomes.