Lady Macbeth is more guilty than Macbeth for two reasons. First, and most important, she premeditated the entire idea of the murder by manipulating Macbeth. She questioned his manhood and resolve. Second, she showed the least remorse. Even when Macbeth trembled at what he had done, she still remained cold and calm, saying that just a little water would take care of the blood. She was the one to go back for the daggers. Lady Macbeth was the one with the least conscience in this play. Even when she went a crazy in the end, she wasn't struggling with guilt in the way that Macbeth did.
At first Macbeth is only half-decided to murder Duncan. It is only with his wife's insistence that he actually follows through with the act. At one point she taunts Macbeth, saying that if he doesn't have the nerve to do it, she will do it herself. This is a subtle attack at his manliness and virility.
Lady Macbeth is the instigator of the murder and in a way seduces her husband to give in to his baser instincts. It is interesting to note that in many countries the law inculpates the person who had the idea to commit a crime more than the one who actually performs the deed.
PERSONALLY I THINK THAT MACBETH,BECAUSE CAUSING OF WITCHES HE BECAME VERY AMBITIOUS AND TRY TO DOING HIS AFFORT IN THIS SIDE ALTHOUGH HE SAY TO ALL IF DESTINY WANT TO MAKE ME THE KING OF SCOTLAND THAN THINGS WILL DEFINITLY COME IN THE SEQUENCE TO HIM.
Regarding to your question, I personally think that Macbeth is more guilty as he is the one who wanted to achieve his dream which is to become the king of Scotland. he feels threatened by Duncan's heir, Malcolm as he will succeed Duncan when he is gone. So, because of his evil ambition, he perform all the killings, tarnish his dignity and others.
Lady Macbeth, in the play is known as "The Fourth Witch" as it was she, who tempted Macbeth to get hold of power through a shortcut. However, Macbeth, himself is more responsible for the catastrophe that befalled him. He was insinuated by his wife to make use of unfair means to reach to the top, but, it was he, who followed her blindly. If he might be having sense and sensibility, he would have pondered longer before killing his hospitable king.
Secondly, Macbeth was having a wish to get the throne by hook or by crook. If it was not so, he was supposed to turn a dear ear to the prediction made by the three witches. But ironically, the witches' words not only remained at the back of his mind, influenced him, but he also shared these weird ideas with his wife. Hence, corresponding to his inward evil, and paving way to dethrone King Duncan, leading him to have a guilty conscience.
His scruples were more faulty as compared to that of his wife. He murdered the King, and after that, his inward wickedness and immorality gained strength as a result of which, he committed one evil after the other.Thus, reaching to the status of Tragic Hero.
Dont forget to remember that he also doesnot fit in the definitionof Tragic Hero given by Aristotle i.e. he must not have any sort of depravity, or moral dilemma. Howvere, Macbeth suffered from this drawback as well. So, i think, it wiuld be justified to claim that Macbeth is more faulty than his wife.
Hope, you will find it interesting.