When creating a SQL Server report and the layout is larger than it fits on an A4 or A3 page, then printing to PDF is the only option to make printing successful.
Adobe PDF format is scalable, i.e. it does not get restricted by the A4 or A3 size as long things are proportional. To explain that:
You set the report size in the report properties to A3 size is 42cm x 29.7 (for large reports) and then check the report body size, if that for example is 43.5 cm, then
the new report size to be set is (43.5 (body size) x 42 (report size)) / (report size - left margin - right margin). Then when you print this report in PDF, you will not get an extra page with only extra column.
The good thing about this way is now you can print in any paper size without any problem.
Let me know if that works for you.