EdgeRight and EdgeBottom determine vscroll & hscroll areas. So, they are not dead areas, just areas designated to initiate scrolling. EdgeRight and EdgeTop are only used for circular scroll (I've never tried to enable circular scroll, whatever that is...). Except for circular scroll, there really isn't any dependencies in the code on the concept of 'center'.
You can turn the "edge" scrolling features off with TrackpadHorizScroll and TrackpadScroll. Two finger scroll will still work.
You should probably run the debug version, and examine the output in console to determine how your trackpad is behaving.
I've ran the debug version. The bottom and right 1/4 of the trackpad that don't respond to tapping or scrolling actually register the tap in console. Here's what shows in console when I single tap once on a close button (which doesn't actually close the app)
Dec 11 12:53:50 --- last message repeated 41 times ---
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (1170,168) z=8 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (2336,340) z=9 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3506,507) z=10 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3508,505) z=10 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3510,501) z=11 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3512,503) z=11 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3510,503) z=11 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3514,503) z=11 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3512,503) z=11 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3512,506) z=11 w=4 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (3511,508) z=2 w=0 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (2340,338) z=0 w=0 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (1170,169) z=0 w=0 mode=(0,0,0) buttons=0 wasdouble=0
Dec 11 12:53:50 localhost kernel[0]: ps2: dx=0, dy=0 (0,0) z=0 w=0 mode=(0,0,0) buttons=0 wasdouble=0
any idea why??