If I have a 36mm front and 23 rear bar how will the handling differ from a 36/24 combo? Is it worth finding a 24mm bar to match the front?

 

You'll be fine. The 24mm rear bar would make the car a bit tighter, but it won't be like your setup will suck. Add the polyurethane bushings to the bar. Supposedly by putting poly mounting bushings on an anti-sway bar, you make the bar "act" like it's larger.

 

The 1 mm won' t make much difference. The smaller rear bar will make it push in the corner(tight), a fatter bar will make it loose. The opposite is true on the front.