The unfortunate truth about the "value" of startup equity is that there is a greater than 80% chance that it will never be worth anything. Pre-money valuations vary widely and don't really matter since they are difficult (if not impossible) to convert into real cash.
Equity (especially early stage and/or restricted equity) is a "bet" on what will happen in the future. It's value is largely in the faith that the recipient has in the ability of the enterprise to grow. That's a good thing, and it serves a different purpose than direct compensation.
Bottom line, initial and growth funding is not a single deal. They are a series of deals in which the details of each deal facilitates or inhibits the next deal. The pie has 100 slices - distribute them wisely.