RootsChat is not for finding living relatives. You can list the ones who are no longer living, but not anyone who is or may be still alive.
In the index at Scotland's People
www.scotlandspeople.gov.uk there are 10 people with surname Paterson and mother's maiden surname Low who died after 1974 (when the mother's maiden name began to be listed in the index). Do any of them match the names you have?
For example there is an Elizabeth Langlands Paterson, born Coupar Angus in 1908, died Perth in 1974. In the index to the 1911 census there is a Paterson household in Coupar Angus consisting of John R, 36; Jane, 28, Bella J, 12; Maggie, 7; James, 6; Alexander, 5; Elizabeth, 2; John, 0.
The births index lists in Coupar Angus Margaret Lowe Paterson, born 1903; James, 1904; Alexander, 1906; Elizabeth Langlands, 1908; John Robertson, 1910; Wilhelmina Walker, 1913. If I am right these could be some of your 11 missing siblings. However there is a gap after 1913, so they must have moved away from Coupar Angus.
I see that four of the 10 deaths were in Perth, and that Elizabeth Langlands Paterson was married in Perth in 1927 to John McEwan McDonald. So it is probable that the family did not move far from Coupar Angus. Wilhelmina Walker Paterson married Martin Toole in Perth in 1938 and died in Perth in 1939, aged only 25.
There's a Mary Ann Paterson, mother's surname Low, who died in Perth in 1979 aged 63. This suggests a birth in 1915 or 1916, and there is indeed a birth of a Mary Ann Paterson in 1916 in Cargill, which is only a few miles from Perth. Mary Ann Paterson married John Chalmers Murray in Perth in 1935 and the other surname of Mary Ann Paterson, mother's surname Low, who died in 1979 was Murray.
Other Patersons born in Cargill are George, 1914; Robert Allan, 1918; Jessie Stewart, 1921; David, 1923. If I am right, those plus Mary Ann would be more of your 11 siblings.
To check whether or not I am right, I suggest that you go to Scotland's People
www.scotlandspeople.gov.uk, buy some few credits and use some of them to look at the original of the 1911 census. Then at the marriage or death of Wilhelmina to see if she is one of your 11 siblings, and at the marriage of Mary Ann to see if she is also a sibling. You won't be able to look at the post-1974 death certificates online, or the births of Jessie and David, because they are too recent, but you should be able to view all the others.
