I realize it’s been a few years but I wanted to add a few items about Gain. First, I believe he may also have been called Gaius. Unfortunately, I don’t have any documents to back this up, but according to handwritten notes from my father (deceased), Gain/Gaius was the son of Hugh Robinson and the grandson of Robert Robertson. Robert, who may have been from Dumbarton, emmigrated to Derry/Londonderry, Northern Ireland in the mid-1600’s. This fits historically with the emmigration plan of protestant “lowlanders” to Northern Ireland encouraged by King James I (James VI). Both Robert and then Hugh were elders in the Presybeterian church (Glendermott Parish). I have no information on the spouses of Robert or Hugh. At some point Hugh must have ended up back in Scotland, as a couple of sources I’ve seen list Gain’s birth as Bannockburn. The link below to a Wiki tree post confirms most of what has been passed down in my family. (I’m descended from Gain’s daughter Elizabeth.) I also remember reading something about Gain being born in Ireland, so perhaps he was born there and then moved to Scotland as a child or young adult. Sadly, there do not seem to be much in the way of records from the 1600 & 1700s. (Not surprising based on limited resources and literacy, not to mention destruction of the parish by the Jacobites in 1689.)
I hope this helps. I wish I had actual documents to back up my information!
https://www.wikitree.com/wiki/Robinson-356