Digital BW, The Print

Hi there guys.

What profile do you guys use in Photoshop when you convert images from RGB
to gray?

Dot gain x% or gamma 1.8 or gamma 2.2?

What is the best (generally speaking) option for QTR?

I know how to color manage when working in color. Adobe RGB and sRGB and all
that. But the black and white spaces are new to me.

I'd appreciate any help.

Thank you

Nelson