NavList:

Here is the form for use with the Flat Bygrave with the special rules. 

https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule/3.JPG?attredirects=0

https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule/Bygraveform2010.pdf?attredirects=0

The rules needed to convert LHA into "H" smaller than 90 degrees are not needed if you are using a calculator since the 90 degrees is a linitation of my version of the bygrave because I eliminated the 180 to 360 scale of the original Bygrave for clarity. Same with the conversion of "X" to "Y" since a calculator has no trouble with angles larger than 90 degrees. 

I see tha Greg gave you the formula 90 - X + L  but the original Bygrave instructions calls for finding co-latitude first, 90 -L = co-lat. you then apply X, either adding or subtracting depending on  whether lat and dec are of same name of contrary name. Using his formula procduced the correct answer so, maybe, it doesn't matter. The formula should be 90 - L +/- X. (plus or minus X) Here is a link to the original Bygrave manual.

https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule/Bygravemanual.pdf?attredirects=0

(Note, what Greg denotes as "X" I denote as "W" and Bygrave denoted as "y" for the first intermediate value. Bygrave also uses "Y" which I find confusing, I have no idea why he couldn't have chosen a different letter for the second intermediate value.)

Here is a link to the description of the Flat Bygrave:

https://sites.google.com/site/fredienoonan/other-flight-navigation-information/modern-bygrave-slide-rule