I also have a Special Agent and Spit Fire and agree they are good forward roll balls. I think the new Sure Fire also fits into this category based on reviews. I'm hoping to get a Sure Fire in the next week or two to go in between the Spit Fire and Special.
The drilling on my Special is based on layout #2 on Storms drill sheet:
http://www.stormbowling.com/pdf/drill_specs/advanced.pdf. This works well on Medium Heavy and some Medium conditions. Great midlane read with a strong continuous back end. A very smooth rolling predictable ball with excellent carry. I've had success with it on Wet/Dry and Med. Heavy house shots, Nationals and on the Shark pattern in my PBA Experience league.
To me the Spit Fire is strong for a pearl ball but fairly versatile. Mine is drilled pin above ring finger, 45 degrees with an x-hole on my pap. It gets easy length with a late midlane read and has a very hard rolling arc at the end. I use it the most on medium conditions. It can work on med-dry conditions if there's some head oil left somewhere on the lanes but it can leave a lot of corner pins if you hit too much dry with it. I prefer to use my Zone Classic on the med-dry shots. I've had success with the Spit Fire on medium house shots, Nationals and on the Cheetah and Chamelion patterns in my PBA league.
