By then it will be too late. It is right now legal advice can help you. The term sheet you have in your hand looks good to you, but only someone with experience from a hundred deals that went awry can look at that term sheet and see what is missing. You have the wrong view of how you use lawyers.

Your process is basically the same as having a lawyer write the code for your web app and then have a programmer review the code just before you launch. Now you are probably thinking "no that's not the same because that won't work". Well, exactly. It won't work.

Reading all your answers here you come across as either very inexperienced or drunk with the prospect of striking it rich or both.