[TowerTalk] grounding quesitons: Ufer, strap, exothermic welds

[Mat Eshpeter]

I am about to pour concrete for the base of my HDX589 tower. I am going to go with a Ufer ground as well as the Polyphaser recommended eight 75' radials with multiple ground rods (8' rods every 16'). Location is on top of a 1600' ridge in WV and lightning is a very real concern. My QRZ web page gives a feel for the location.
 
To build the Ufer ground, I am thinking about connecting a single bare 2/0 stranded copper wire to the rebar. Questions:
1) is one enough?
2) how do I properly connect the copper to the rebar? Is exothermic weld the only way? Any problem with dissimilar metals?
3) how should the copper exit the base slab - above grade or below grade?
 
Also, seems that copper strap is the preferred ground material for connecting rods together. Will 0.032" thick strap have significantly better longevity than 0.022" strap? I am refering to the strap sold by Georgia Copper.  Copper is expensive and I don't want to invest in copper that won't add any value to my installation. 
 
Where can I find exothermic weld products to connect copper strap to 5/8" copper clad ground rods? I am exhausted reading Harger, Erico, Terraweld info, and can only find wire-to-ground rod products, no strap-to-rod products. 
 
73
Mat
KK1C