FWIW, sometimes it possible to easily modify the chainring by changing the tooth profile at two locations 180 apart from the other. For the off-road tandem that ran single speed full profile tooth patterns for a middle ring, I copied the location and tooth profile from a chainring known to shift well. 5 minutes of modification and the chain easily is walked from middle to granny, where before it was as the op mentioned, not consistent and required little or no pedal pressure.

PK