Anthony
I have no doubt that Sutherland was the greater influence on Ross, as the two we both natives of Dornoch and worked together there for some time sharing greenkeeping/design ideas as well as playing golf together. Ross also came back from the USA several times to Dornoch, firstly in 1910. That being said, his time in St. Andrews, where he had frequent and significant interaction with Old Tom and the other golfing worthies of that time, was probably also highly influential, paricularly as it happened in the early years of his adulthood, and after Sutherland had already noted his golfing ability. I would doubt if he did any golfing tours with OTM in the 1893-1895 period he was at St. Andrews, but I could be wrong. It is more probable that he helped out Sutherland in the work he did at Brora and perhaps elsewhere.
Tom MacW
According to newspaper accounts, the 2nd 9 at Brora was opened August 1897, so it is very possible that Ross could have been involved with Sutherland in that work. Also, to assert as you did above that Sutherland is "the unsung hero" at Dornoch is very naive. He is and has always been credited with his signficant contributions to the architecture and agronomy of Royal Dornoch, building on and continuously improving Old Tom's initial design, by the people who count--the people of Dornoch. He is unsung only to those who are tone deaf or just have never cared about GCA.
Rich