One parikaram I can suggest is that You parayan Hanuman chalisa daily. Lord Anjaneya is the only deity who can conquer all navagrahas and can protect you from any ill effects of navagrahas. This is my personal experience and who has reduced the ill effects of saniswaran during astamasani. If you have time and will you garland him with 108 vadas and chant hanuman chalisa 108 times.