Front vs rear wheel sizes for best handling

The only thing I can add or say that I have done has been just to follow what I have read to as far as I want to take it. In other words, I'm not making a Ralley car. But I will drive it hard once in awhile. With that said, the best upgrades I can suggest without breaking the bank and getting into over the top modifications is simplely to do these parts new and a bit thicker. Street versions. Personal tastes vary.

Thicker T-bars and heavier duty rear springs. Small block cars will like big block T-bars or even the upgraded units for better handling. HEMI/440 springs at the rear.
Increased size/thickness, anti roll bars
Excellent shocks. And excellent shocks will cost the most. Even the basic QA1's.

As mentioned, tire size can be tricky. I have not investigated a whole lot in this area. I have been happy and confident on the road enough with the same size tire in all 4 corners.

Will off set widths and diameters help?
Probably so but I did say I'm good with the same size on all 4 corners and have not investigated with a lot of varying widths. I have run them, just not made comparable bites to make a good suggestion.

I myself like as wide as a tire I can get under the car for best results but do not go to the size of looking stupid.