Not all Grunts can afford to forgo salary and may require at least a nominal income to make ends meet. In these cases you should deduct the amount paid to the Grunt from the base salary and use the remainder to calculate the GHRR.
For instance, if a Grunt made $100,000 in their last job their GHRR would be $100,000 x 2 ÷ 2000 which equals $100. If the company paid them a $50,000 salary you would subtract that amount from the base so the new GHRR would be $50,000 x 2 ÷ 2000 which equals $50. In other words, your pie slice is based on whatever compensation is put at risk.
Let me qualify this with a quick note: not all Grunts will earn equity in your business. Sometimes you'll hire a Grunt, pay it a salary and everything is fine and fair. These "mercenary Grunts" are generally more entry-level or with skills that are relatively easy to replace. For instance, a receptionist, a junior web developer, a customer service rep, an entry-level sales rep, unpaid interns and any number of other positions who offer tactical, but probably not strategic, value to the firm. If you can't pay them, however, you will probably have to cut them in.