Companies should always raise money when they can and not when they have too... If you don't believe me then do your homework; try Googling for more information.
When you start looking for money, and you probably should, please consider taking the handcuffs off some of your larger investors (like Jack) and let them increase their position without losing their investor status. I suspect Jack would gladly invest more (to dollar cost average down) but current agreements take away his ability to control his own shares if he buys more... It might be worth considering convertables so new investors can lend you money with the option to convert at a later time (if/when it makes sense).