Mercury in Aquarius
The sixth house falls in Cancer and is ruled by the Moon. The methods you use to persuade are associated with the expression of strong emotions and with your ability to awaken the emotions of others, to tempt them in some way. Your strength is to exert emotional influence through laughter, excitement, sadness, tears, to infect with emotion. The Moon is a very variable planet (its phases prove it) as well as intuitive and receptive, it "loves" to receive, it is the largest consumer of sunlight. Therefore, sometimes you can resort to temptation and seduction, place baits (especially gifts) to be persuasive. You yourself also succumb to this strategy of persuasion.
Mercury in Pisces
The sixth house falls in Leo and is ruled by the sun. The methods you use to persuade are related to the demonstration of superiority, which clearly shows others that they have to trust you and support you. You actively use compliments and flattery that make others feel good and unconditionally surrender to you. Your strength lies in the inner confidence that no one can refuse you. The Sun is the only "charger" of the rest of the planets and they all go round it. Therefore, your methods of persuasion often have the meaning of "You have no choice but to agree with me." You yourself also succumb to this strategy of persuasion.