Hi Sara,
As a caveat there are some very good local early census records although it’s true to say on the whole they are not as useful to a genealogist and some of these are available commercially and not on the Scotland’s people list.
Let me explain: The census was taken, as it is today, for statistical purposes. So somebody was given the job of compiling the statistics. How would they go about it? Some, by no means all, wrote down the heads of each household together with the statistics others wrote down details of the entire household, much more like the 1841 census. So what happened to these notebooks? They didn’t need to be sent with the census at the time so some stayed and ended up in local libraries or archives, others have found there way to the National Archives and of course some will have been destroyed.
There are also census alternatives, Applegarth Parish List 1697 for example and of course the Hearth Tax records can be useful too.
I would recommend contacting the family history society, which covers the parish you are interested in, as they will know what exists locally and what has been published.
On a related point, if you have traced your family back to 1841 I would also recommend the Scottish archive network’s knowledge base:
www.scan.org.uk/knowledgebase I use it constantly!
Hope this helps,
Emma