Good advice from all the pros.
Here is a few thoughts on the driver plate. Depending on your lower leg shape and fit into the boot, a driver plate can have 2 completly different effects. The length of your lower leg, your strength, the way the boot contacts your instep and ankle area, your style of driving the ski (edge angle vs. rotary force), can all effect the way a driver plate will work.
For some adding the plate can bring leverage higher up the leg and make the boot feel softer because of the incresed leverage over the cuff drives it easier over the lower shell. For others it will feel like the boot has stiffened.
Also the placement is a big factor in net feel. If the driver plate is raised high above the cuff strap (5 to 30mm). it will have a different feel then simply putting it in even with the top of the cuff.
So...Take CEM's advice take a driver plate or polyethylene plate and just slide it in beneath the cuff straps and ski for a day. During the course of the day try it high, then try it low and see what feells best. These combinations with a expert booster strap could also be tested without permanent installation.
With numb toes, it is usually nerve or blood flow related, and a good bootfitter should be able to swim upstream from the numbness to locate the cause. My list of top choices: check ankle range of motion, (limited range brings greater force onto ball of foot and toes in skiing, especially with a boot that has easy forward flex) Check the base of support (footbed) for proper trim, molding at the toe, raised 1st or 5th, or just overall volume. Check width compression at ball of foot( possible nerve copression between met heads. And last but not least pressure on the instep ( over buckling? )
The best advice the pros have already given to you: Find a good boot fitter that can help guide you through the discovery process.