Writing an Offer for Bed & Breakfast: Contingencies

I am about to write an offer for a Bed & Breakfast. 

I would like to know the "right" duration for the main contingencies (and whether I need to add more contingencies to be safe)

1 - Inspection contingencies: how long should I put?

2 - Feasibility contingencies: how long should I put?

3 - Financial contingencies: how long should I put?

Other contingencies?