There is some current work in progress, but I question the use of 1.28c.
1.28c does not use planesets, whereas 1.28e and 1.29 do.
If the only reason to use 1.28c is the 640x480 screens then surely it is better to use either the special 640x480 version of 1.28e or the special 640x480 version of 1.29.
These exes have several improvements and additional features which are not available in 1.28c
Jel