I am far from an authority on sails, but I think you can mostly account for sheeting angles by going to a higher cut clew. That way, you get three advantages (IMHO):
1. smaller sail area that you desire
2. ability to use the existing tracks
3. better visibility under the sail

Here is a related question. If there are no other factors of concern, is there a big difference in sail performance between (for example) a high-clew 135% and a low clew-120% of equal sail area?

Just curious if the aspect ratio of the sail is that critical (especially for cruisers).

There is a difference, but it is not aspect-ratio driven.

The low clewed sail will be more efficient upwind, with a shorter foot length, the foot closer to the deck and more parralel, and better control of leach tension through the sheet. Race boats tend to carry low clews.

The high clewed sail will be more efficient reaching and running, because it has more area up high, and the top of the sail will twist off less when the sail is eased. Race boats carry a sail called a Jib Top Reacher with a high clew like this.

Finally, you can't have a 120 and a 135 of the same area, the numbers relate to LP, not foot length, and LP doesn't care about clew height. If you move the clew up, the LP measurement stays the same and the area stays the same, you just move sail from the foot to the upper leach.

Thanks, Jason. I learned a lot.

At first, it was not intuitive that the high-clew sail had equivalent area, but thinking about the geometry more, I see where you are right.

Once you wrap your head around it, it's simple.

It also follows that the standard 'cruising' jib with a high clew, also has correspondingly more sail area up high and will tend to make the boat heel further for a given LP size.

Nonetheless, since most cruisers spend more time reaching and running than beating (hopefully), the high clewed sail tends to be more versatile and lasts longer since the leach loads are lower. This is the first part of the sail to get damaged on a race boat.