After a lot of different models from all flying to really narrow elevators I've found that if the trailing edge moves the same amount that all the different setups work about the same. So if a 15% wide elevator needs plus and minus 1/4 inch of travel at the trailing edge that if you make the elevator 50% of the chord it still needs the same plus or minus 1/4 inch. You see, it seems to come down to how much does the overall airfoil angle of attack change.