Assuming you don't want to re-drill your ball, to reduce perceived 'flip' means you have to reduce 'flair'.
Extender Polish will reduce flair, but will also increase skid. This effect doesn't last more than a game or 2. Maybe less if you get good RPM's.
A more promising approach would be to get slightly inside of your ball and stay there through the release. Axis rotation will be decreased, skid will be decreased and friction will occur earlier. Since more RPM's will be scrubbed off earlier, flair will be reduce and hook will be decreased. What was angular becomes a smooth arc.
During this process, watch carefully how your ball reacts in the pocket. If you remove too much axis rotation, you'll begin to hang weak 10's.
The angle you use to the pocket is also important. Most people as they move left begin to over-compensate by turning over their wrists which simply increase axis rotation and defeats the whole purpose.
Try not to get caught up visually with your ball's motion. It may seem to move a lot, but if it gets to the pocket without enough RPM's is will simply deflect.
Instead, try to find the most direct line to the pocket, that uses the least RPM's but will still carry. Only the Belmos and Tacketts of this world can wing it from gutter to gutter and still have enough to carry after their ball recovers.
With the new equipment, we can all create huge hooks, but we can't all create the RPM's necessary to carry more strikes. Usually, just the opposite occurs.
15 lb Storm Hy-Road : 65 x 3-3/8 x 25 500/1000 Grit
15 lb Storm Hy-Road : 50 x 5 x 50 Polished
14 lb Ebonite Cyclone : 50 x 5 x 50 Polished
15 lb Columbia Blue Dot: Circa 1978
325 RPM'a @ 16 MPH