The options I see are:
1. Assume some volume of sales per sales person and then calculate total revenue based on sales heads.
2. Assume some revenue target and assign a quota to each salesperson and calcualte the number of sales people.
3. Assume some cost to acquire each customer, set a marketing space and calculate the number of new customers based on marketing spend/cost per acquiisiton.
Doing forecasting need to determine:
1) the sources of revenue and the revenue drivers
2) the classification of costs and the costs drivers
3) the nature of costs and their patterns
Then you develop profit and loss + balance sheet + cash flows forecast.
With the above basis, you can perform the cost of customer acquisition per type of revenue per year; the cost of customer acquisition & maintenance / total lifetime revenue for ROI or NPV; break-even, the margin of safety, contribution per sales type; ROCE; market sensitive test; etc.
If you adopt the above, you will somewhat be getting things in the proper place.
Hi - Just checking to see if you got what you needed.
I'm an experienced CEO. I build financial models for all sorts of businesses, including recurring revenue and/or project based businesses like SaaS. Your three points above hit some but not all parts of a solid financial model. Other parts would include cost of delivery, support, general admin, etc. And don't forget to tie all that together with cashflow analysis and valuation. Since you're pre-seed stage, your Seed investors will want to run the numbers. Best to start with what you think not what they can make up for you.
If you still need help, set-up a call and I'll be able to give you more specifics based on our discussion.