Business Modelling

Hi I need 2 different What If Scenarios developed in an Excel Spreadsheet which will give me a few fields I need to enter, and it will spit out the scenarios. All the scenarios are for a sales environment and will be used to assess the ROI of various strategies. They are all about measuring the impact of a variable client attrition rates, (and its cost in terms of man hours and sales staff costs to replace) & the impact of existing active clients and how much they are likely to buy (and the cost in terms of man hours and sales staff costs to get that business), and how much new business development activities I need to also pursue (in terms of cost of man hours & sales staff costs to get that business) in order to achieve a certain sales revenue growth over a year. There is a linear model assuming all clients are equal. The 2nd scenario is the same but based on the 80/20 rule (ie 20% of your clients represent 80% of your business), where the impact of losing some of the value of my 20% top clients is much higher. It needs to looks aesethic and smart as I will be presenting it to clients. It needs to be easy to use. Backend workings need to be available as part of client due dilligence. If you have any queries please contact me because I'm not entirely sure my notes attached will answer every question.