M42 - imaging / exposure time and gain setting for live stacking in sharpcap

I’m new to the forum and AP imaging. Wondering what time exp. and gain settings for my light subs, during live stacking in Sharpcap.
My rig:
70mm ED Refractor with 0.8X reducer/field flattener.
Imaging camera ASI533mc Pro
EQ Mount/ iEXOS-100
206mm guide scope with mini camera
Imaging software SharpCap pro 4.0
Acquisition - Cartes Du Ciel