In a company with two directors, one is to be the head. Is it necessary that the head must have more shares as compared to the other for exercising his powers. Does a share ratio of 51:49 serves this purpose?
There are two primary schools of thought for this:
1) Someone must always be the boss. Having an unequal distribution of shares (and presumably unequal job titles, CEO vs VP of Engineering for instance) clearly indicates who has the tie-breaking vote when it comes to making business decisions. This means the person with the lower number of shares might find themselves implementing ideas they do not agree with.
2) In a partnership, all decisions must be agreed with. On the other hand, what possible situation will there be that you two will disagree with something on? I have found that in running a small company (in my case, with two other people), we generally worked together on ideas, listened to each other, had our own points of view, but in the end we all came up with the best approach and worked together to implement it. No one ever said "I have more shares than you, so you must do it my way". In the trenches of a startup, everyone works together, titles don't mean anything, and all decisions must be agreed on or else you'll have things being done that you don't truly believe in that will fail.
I think you need to seriously think WHY you need an uneven distribution. It's likely to cause more problems than it solves.
Also, have the founders agreement in place before you start working! What happens when one of you wants to leave the business after 1 year? What happens when one of you dies? These are questions easier to answer before you start than after, when one of you wants to leave the business but the business continues on - do you still keep your 50%?