1) I see you are a Realtor, I would definitely talk to your broker about the 60 day clause because local markets will vary.
2) in my market this clause would probably not fly for an mls property as most properties are being purchased cash. Would you take a 60 day clause vs cash?
3) if you are sourcing deals off mls, then you could use this clause and see if they bite.
The better of a buyers lust you have the less time you need to source financing, I would be inclined to use the longer term with no buyers list and then use the deal you have to build a buyers list. I am not a lawyer but your broker can be of much help when it comes to protecting your self in contracts.