With a new or unfamiliar pistol, I usually start by using my support hand to place the pistol in my firing hand with the barrel as directly aligned to the line of my forearm between elbow and wrist as possible. Then I raise the pistol to my firing stance, applying only minimal muscle tension. I look at my sight picture, and if the sights don't naturally align, I will rotate my grip counter-clockwise or clockwise and repeat the process until the sights align automatically and naturally. Then I practice addressing my grip in that orientation when drawing and presenting to the firing stance. The other factor you might need to assess, is your trigger pull. The 1911 takes all the work out of pressing straight to the rear for you. Most polymer pistols have the "hinged" trigger that pivots around a pin, so achieving a straight trigger pull means overcoming the tendency to "torque" the pistol while you are effectively moving pressure around a hinge on a lever.
Again, I'm no expert, this is just my good 'ol boy $.02, but hopefully it gives you food for thought.