my humble opinion is that sounds like a fair deal. there are 7 people and the founders always deserve a bit more due to the idea concept and effort to make it work. In the end you are going to develop something so you need to think in terms of how much money you will get calculating the probability to get much more than what you would in a normal job. If there is a 10% chance that you 10x the money you would get normally that's a fair deal. If you think this can go big then maybe there is a 10% chance you 100x the normal wage. This is a good arbitrage. Don't get greedy because "10% sounds little". If you think this project is not going to generate much and you don't believe in its potential just say no.