I use suite of tools from MS SQL Server 2012 (BI Stack), through Excel 2013 and even a little Cognos Insight and on some occasions R. In all cases I’ll ask for the data set(s) or a representative sampling before accepting any work. I do this because I want to ensure I can indeed process the information before accepting a job only to find out the data set cannot provide the insights you are looking for. I have worked on record set sizes from 50K to 10M+ rows. As long as it is practical to send online I can support the volume. Typically, but not always, the result sets are delivered in the form of a workbook with multiple spreadsheets containing aggregate data and supporting graphs. With Cognos it may be a graph and with R a script that generates a graph.