Well, given that his yacht cost US$70 million, and the Gulfstream G650 was US$65 million, then he's got to sell quite a lot of V4's to keep those running...
When the DC01 was first marketed, everyone told him it was far too expensive to sell in any numbers. Clearly, they were wrong.
I believe he is already a multi-billionaire Rusty, net worth around US$6 billion. The nice thing about having no shareholders to worry about is that you can pay yourself whatever dividend you like (£111 million last year I think).