I recently had an incident with my car which resulted in messed up toes on my car.

I plan to run 19x9 and 19x10 +5 rims on my GS which I was told it will sit flush.

I understand that adjusting the camber will change the toe, but the wheel set up is currently not sitting as I expected so question is, does toe affect how much camber I can get? Will adjusting toe allow more negative camber?

Camber is currently maxed out.

 

No toe will not affect your maximum/minimum camber range. If you want to gain more adjustment to your camber/toe you should purchase either Battle Version or FIGS rear adjustable camber arms and toe links.

IMHO wreck or not these are must have upgrades for rear suspension.