http://www.scotcourts.gov.uk/library/civil/estates/docs/smallest.pdfgives some insight into the current procedures regarding "small estates" although the figure quoted there is £25,000
prior to 1964 the system of primogeniture was in place and the eldest son would have got all of the heritable property with the movable estate being divided into 3 equal parts (2 if there were no children).
the widow's part - jus relictae
the bairns' part - legitim
the dead's part - deid's part
One case example given is of a widow left £2000 in a will challenging the will and claiming her legal right (jus relictae) to a third of the movable estate.
I am not sure if there would have been a limit in those days but common sense (not often found in the Law) dictates that there must have been one