In my only experience with PETG so far I had success with adhesion on glass with hairspray and no warping. But it was a relatively small part (my motorcycle turn signal mount). I think I printed it at 245C with bed temp 60C. Not sure about the fans and such, I just left that the default in the profile in S3D. But I don't recall if I used the PLA or ABS profile (S3D doesn't have a PETG profile for my printer). I used one of those and adjusted the temps. I had other issues with the part being weak and the surface being rough but I think that was because I bought a PETG filament with carbon fiber and it probably wasn't the best choice for a thin wall application.