Sound and spelling variation in Older Scots

I am a team-member in the AHRC-funded From Inglis to Scots (FITS) project project, mapping sounds to spellings in the earliest documentary records for the Scots Language. Our source materials are the etymologically Germanic root morphemes in the tagged texts of the Linguistic Atlas of Older Scots (LAOS).
Our objective is to try to track individual morphemes and segments’ development through time and space, in order to (re)build the phonological history of the earliest period of the language “from the bottom up”. To this effect, spelling – and variation therein – is crucial. We will be mapping written forms to presumed sounds, and placing their variation across time and space in order to retrieve representative patterns.
A sample mapping of sounds to spellings (and vice-versa), from the FITS database: