200 or 320; depends on lighting and skin tone and affect desired.
ei rating is what makes hie difficult to control. to control ei and the rest of the process is what makes it belong to the individual. for this shot - ei 100 and extended development by 10% which gave me the high key and grain that i desired.
keep shooting your current method; your hie post is spot on for your subject.
well, you managed to capture shadow detail and maintain highlight hie goodness. you clearly have an eye for composition. keep at it; hie is no different than wanting something more from something less.