The 80ᚼ Pareto principle is based on Pareto's theory that 80% of the results one gets in a particular endeavour will be mainly due to 20% of areas to which one has applied efforts. In business this principle has been found to be true. Your data, properly converted into appropriate performance indicators, will show you where your largest margins come from. You can then channel more time and effort in that direction.
Deciding What Spreadsheet Application To Use. This would ultimately be up to you. The big "fight" has always been between Lotus 1θι and Microsoft Excel. I started out with Lotus 1θι back in 1993 and learnt Lotus Macros programming(via self_tutoring). I eventually used this skill to develop _ in my free time _ various custom spreadsheet solutions(that were formally adopted for use in the departments I worked in as a brewer/manager in Guinness), before switching to Microsoft Excel in 2001. Subsequently, I developed my Excel Visual Basic spreadsheet programming skills (also via self_tutoring), because the company had chosen to adopt MS Office during the roll over to year 2000.
In effect what I am saying is that companies which get the most value from spreadsheet automation(including using it to avoid expenditure on less adaptable commercial off the shelf applications) will be those which empower their users to routinely generate "in house" solutions. In such companies, you will find that only when the requirement becomes considerably specialised or complex, does the IT department get called upon to develop or purchase software solutions for user departments or functions with significant data recording and analysis needs.
Custom spreadsheet solutions which survive long after the developer has "left the scene", are often those which users accept because they discover it _ among other benefits _ makes their work quicker and easier to do. That is why the best person to develop such solutions tend to be one who works in that area, and is therefore familiar with the way the manual system operates. S/he would have an "insider's" perspective of the best way to introduce automation other users will readily adopt _ even as it solves the identified problem(s).