I've updated my COIL.EXE program from the 1990s with more accurate methods and an optimizer. I include accuracy data for a couple dozen coils measured with an HP 4342A Q Meter. By LowFER request, form material includes HDPE since LF antenna loading coils may be wound on an HDPE plastic bucket. The program runs in Windows.
http://ham-radio.com/k6sti/coil.zipBrian