If the track is going to be pitched then extension springs won't suffice for the job. Extension springs will not hold the door in the header because it won't have enough "pull" while in the open position (the springs will be relaxed) to defeat the weight of the door (the door will be trying to roll down the track) in an inclined track.
A Torsion system using the proper drums will hold the door in the open position, out of the header, on a pitched track application far better than an extension spring system would, but I don't think you truly understand the concepts at play here.
There are various configurations of drums to be used with either regular headroom, high lift, or vertical lift applications. The drums to be used here will depend upon the amount of pitch of the inclined tracks.
Evidently you have never worked on an track system other than a normal horizontal tracks.... if that.
Rather specialized tools!!! Two plain steel rods are the only additional tools used to do the job. This comment of yours exposes the fact that you're not very familiar with garage door torsion springs.
Sure the motor can hold the door open but you shouldn't depend on the motor to hold a door up that hangs in the header. The door should work smoothly and stop in a normal position under manual operation. Using the opener to force the door higher because the springs can't do it is obviously putting more of a load on the operator.
Install the proper equipment/parts for the job at hand so you don't have to "jury rig" your door.
It's not rocket science Pop, it's really quite elementary. ;-)
Rich