Doubt in Required no of bands

[Agathyan Barathi]

Dear all, 

I have a doubt in using the total no of bands needed to GW Band Structure. How many bands should I take for a homobilayer TMD system, if I take 'N' bands for the same system in monolayer.

Should I double the no of bands? or Should I just add excess bands in bilayer calculation.

In short, 

If I have 15 bands in monolayer and have the optimized GW bandstructure at 100 bands.

For 30 bands in bilayer, should I double the bands to 200 or increase it by 30 i.e. 130 bands