If you are going to begin spending money and time on a project I would take the precautions of ensuring the agreement is written so if your funding decides to pull their resources or not collaborate with you for the project you have a written agreement show they must go through with the project. However if you are deciding a simple decision of where and when to present the project to possible investors a simple verbal agreement will suffice. Often times to prosecute a dilemma rooted from a verbal agreement you are going to need a witness to provide evidence this agreement existed. If there is a witness sitting in on a agreement they are most likely going to record the agreement in some form of paperwork which will suffice as evidence. Therefore if I was in a position of power I would ensure all agreements are written to decrease chances of dilemma and conflict.