Standing Z

iTrader: (58)

My current rear toe is at -1, and was wondering if I flip the arrow on the rear eccentric bolt how much more negative toe will I get?

FYI, yes I did search.

son of krypton

iTrader: (4)

I think you are mixing up camber vs toe. I believe the rear camber bolt can do a max of -2*. To help the car rotate a little better, you need a little more toe in in the rear..

boomn29

iTrader: (47)

I'd hope your rear toe isn't -1!

Ideally - mostly for tire wear - you want your toe close to 0 all around. Some people try to trick the car and force it to turn in AutoX with big amounts of toe-out (like up to 1/4") but it's not recommended.
I'd recommend adding camber in the front. Yes you can flip the bolt, you can and camber plates to the stock suspension too for cheap if you want even more.