I would NOT use any reinforcing steel. Reinforcing steel is used for: 1) Flexural control (tension steel), or 2) Crack Control (temperature steel).
1) Flexural Control: When concrete “bends” , (like in concrete beams or elevated slabs,) the bottom of the section is in tension. Concrete is not good in tension, so reinforcing steel is used. This is NOT your issue.
2) Crack Control: When concrete is poured, it shrinks. That shrinkage is controlled by reinforcing steel and/or the size of the pour which is controlled by “control joints”.
Your situation is strictly bearing (no bending) so shrinkage can be controlled with “control joints”. Actually, a more accurate description is “shrinkage joints”, as concrete is the largest it’s ever going to be the day it’s poured. It will continue shrinking throughout its life. (Yes, in extreme hot climates it will expand, but never to its original installed size.)
I’d forget the reinforcing steel, especially reinforcing wire, because: 1) there’s never enough because it’s too small for the steel-concrete ratio required (See Pe factor), and 2) it’s always in the bottom, which causes cracks by keeping the bottom portion of the slab from shrinking during curing at the same rate as the top portion of the slab.
Depend on where you live, I’d keep the control joints 1) square, and 2) at about 12’ oc each way for exterior slabs. I’d check with some local contractors and verify my 12’ estimate. (It’ll be less in extreme hot-cold environments and more in temperate climates.)