The ratio of ginger to garlic which is 1:1 is what most people follow and one which I also follow. But then again it depends on personal preferences. Feel free to increase the garlic and use a proportion of 1:2 or inversely use a proportion of 2:1 for the ginger and garlic respectively. I would suggest to make a small batch using your proportions. While making Indian food, use the homemade ginger garlic paste and see how does your recipe or dish tastes. If has too much of a garlic flavor or more of the ginger flavors, then change the proportions accordingly.