Hello Greg,
Let me know if you have a question and I will do my best to answer.
I am far from being authoritative on the subject, with only an intermediate level understanding. But as an Armiger I have taken an interest over several decades.
I was first introduced to both genealogy and heraldry as a boy by my grandfather, and as I am a painter, I have appreciated the art and expertise of Heraldic Artists over many years.
I also read Cultural Studies at university and symbology is as ancient as the first mark making in human society. Symbols generate meaning and communities and families organise themselves accordingly.
The Stodart system of cadency is a good place to start. This is all conditional on the original stem Arms and also if one holds quartered Arms, via an heiress.
http://en.wikipedia.org/wiki/File:Differencing-en.pngAlso I have included a link to Scots Heraldry at Google Books. The author Sir Thomas Innes of Learney, was a previous Lord Lyon.
http://books.google.com.au/books?id=7JB ... ry&f=falsePlease also find a link to a free ebook copy of, The Law and Practice of Heraldry in Scotland by George Seton.
http://books.google.com.au/books?id=exw ... ry&f=falseThese are great books to start ones reading.
All the very best!
Grant MacLea South, Esq.
Hereditary Fletcher of Clan MacLea.
Cadet of Achnacree.