It probably won't help much. You can put more rungs on a ladder, but it won't stiffen it much compared to tube chassis, or uni-body designs. It will...
It looks like you could use a thicker rubber bushing between the end of the spring and the spindle, which would raise it an inch for sure. Bolt looks...
I chose not to use coil overs for several reasons, and I kept the weight of my car to near the same as a 96 Corvette running the stock size 275/40-17...
Assuming you never let the reservoir fluid run out while bleeding and pulled at least a quart through the system, I would suspect the master cylinder...