Double masking prescribed by government led scientific pannel on covid 19 , so it's formulated because of reports suggested general public never wear mask properly !!! Difficulty in breathing by double mask is only in a state of mind , think everyone in Covid ward wrapped in ppe kit but all are working , if there is pathological difficulty in breathing because of double mask or ppe then those people never make this happen !!

Single n95 mask is sufficient If n95 mask is not available,  you should wear cloth mask with surgical mask

Yes single N95 mask is good and sufficient

Double mass preferred in crowded area but otherwise single mask is sufficient if it’s n95

Double masking ( one surgical and on top of it a cotton mask )

If you are wearing a proper N 95 mask then only that is enough. But if people are wearing a cloth mask they should use a surgical mask inside and  on that a cloth mask. For protection.

If single N95 mask used thn no need for double masking. If cloth or surgical mask thn go for double.