Even if, already from two centuries, in all the nations, engineers and scientists have tried of to reach an unification of the different quantities that are used in industry and in science and hundreds of International Conferences have been made for adopting the same definitions all over the world (and this for the obvious reasons of clarity in transmitting data and results), in my opinion everyone can do as he please and choose, in his calculations and jobs, the units that are more congenial to him and that he prefers for traditional or personal reasons. If then the conversion between these personal units and those recognized (and understood) from others is not made, there will be some difficulties inthe communication and in the comprehension :-)
Returning to the Longitude, also I prefer the range from -180 to +180 degrees and I believe that this is not important because of the periodicity of the trigonometric functions that use these values. For the Longitude's Sign instead, if there is some difficulties in using (in our writings) the IAU convention (Long. positive if East), we could not to use the signs and speak only of East or West Longitude Everyone then, for a East/West Longitude, will put the necessary sign to get correct results with the formulas that he uses. Best wishes Gianni Ferrari
