Do i need 8 or 7 shade for low amp tig welding

Hi there I'm about to by a new welding helmet and a want to know if my helmet need to go lower than shade 9 for welding thin materials like 0.5 to 1 mm tanks

I have had no problems with mine.

Everyone's eyes are different and ambient lighting makes a BIG difference. Personally i don't have any problems seeing what i'm doing through a shade 9 when welding stuff thinner than that at around 14A or less provided the lighting's good