I'll always preach lean bulking for natural skinny people with fast metabolisms like myself who've been very skinny all their lives. Theres really no point in dirty bulking then cutting when you're already thin. Just be patient. It took my 4 years to gain 45lbs, but it's a quality 45lbs. Even 10bs of muscle makes a huge difference on a lean body. Think about buying 10lbs of lean ground beef from the grocery store putting that on your body lol.