I've got a Spot Hogg (hogg-it hunter) on my Z28 and I've got a 4 pin config., all green fibers, top pin .029 (old eyes), remaining 3 pins .019. It's built very well and solid. Pins are very bright, and it's a breeze to adjust.
I also have the Axcel Armortech hd. It is equally as good if not a smidge better IMO than the Spot Hogg. Both are top quality sights.