Hi Kevin. Thank you for your wife's Mackison line, although you dont give her first name.
Did you know that James Mackison (b1816) married twice and that Thomas (b1867) was married three times?
I have some rough family trees that I hand-drew (back in 1985! -pre Internet) which I will scan and send to you to give your wife some idea of the various branches, in case you arent already aware of them.
In the meantime the testament that I referred to was for John Mackison, tenant at Newhouse, parish of St.Ninians, 1st July 1743, Stirling Commissary Court. Now of course it is available on the Scotlands People website for £5 so I think I will have a look at it.
I have attached a similar 'family history' written for my father about the Forfar family in Bannockburn. It has my Mackison ancestry appended. If you would like the back up details then please let me know. Jim