Question on pulling fenders..

[rupertaker1]

I've searched and haven't found much more than ''heat them up and roll back and forth''

I know to cut the paint so it doesn't crack, and heat the outside and inside with a torch so it will stretch easier...but is there a certain angle to start at with the fender roller? Is it better to start at a 45 degree angle and then work my way out so its perpendicular to the ground? Like start at ''\" and work my way out to "|", or should I do vice versa? I've practiced on a few friends cars and have the basics down but I'm hopefully doing my car today and just wanted to iron out the details...wish me luck, I'm trying to shove 18x9-4 and 18x10-2 in under there without looking too mexican =)