Well, in that situation there are 2 things.
First thing is that the letter has to contain that information. Your letter doesn't, which is bad. Payslips are not a supplement for things not mentioned in the letter. The requirement is that one document has to have all the information required. It doesn't say that you can gather salary from here, number of hours from there and all the documents have some part of evidence but no document provides the entire picture.
That being said, if you don't have the number of hours, providing payslips would be better than not providing anything.
However, even with the payslips you are likely to get "Review Required" for work experience and get stuck in the process for some time because you did not provide IRCC with one document that they require.