[willy]

You can trim them off, I've done that on a previous boat but the problem is you cannot count on them to secure your rod and reel in a chop or if a good size fish hits and then goes slack, I had one jump almost out of the holder twice just barely got it in time.
They do make them with different angles to them which might help or you can cut off 8 inchers and use those rod holder inserts that fit inside and angle the rods out for trolling.
You can also make or buy from Cabelas and others a rack that you can put on or take off that has multiple rod holders or mounts for down riggers that go across your transom, they are popular with steelheaders and other big lake fisherman. Maybe Reelapeelin or Mac Attack can tell you more about them.