Lots of good info. there Allan, but you are dead wrong that you have to use a pivot fence with a 14" saw. What your saw is telling you is that it needs a new blade, or the blade needs to be moved on the wheels, or the wheels need to be aligned. My 14" Delta with riser cuts beautifully straight as long as I do those three things. I use a 7" shop made straight fence set parallel with the miter slot and regularly baloney slice nice straight veneers or resaw stock. 10"+ hard maple, oak, etc. I often get tolerances of no more than 0.005" on 3/32" slices 10" wide and 3 to 5 feet long. A bad day is a deviation of 0.010".
Moving up to a bigger saw will make it easier because you can run higher tension (compared to a CI Delta), but the basics are still the same.
John