I agree with product-people-profit. It is awfully hard to make profit in early stages (first few months). But I understand the OP view that profit is key because we have seen excess of everything else except profit.
We built initial version of a saas product (2 people). After initial traction, we decided to add people who will directly work on the product or support/customer on-boarding.
First objective at product launch was to make 10 paying customers happy. At 100 paying customers, we have added some more people.
It is not a science but profit will usually follow a product that customers are willing to pay to get their problem solved. Keep the customer metrics (count, churn, product usage, reviews) the center of all your decisions.
- My reference to product above is B2B saas.