Depends on how much time and effort you want to put into it, wether or not you are motivated by the largest yield, etc. I am currently helping a buddy out who is doing the exact same thing.

Big lots end up with less of a yield, but also take far less labor on your end and you get rid of everything. Nothing left over to discard of. Downside is it limits your target pool as it tends to be more of a local pickup kind of thing.

Individual piece by piece is a larger yield, but also more labor spent.Not to mention packing supplies

For my friend he is doing a mix of selling in smaller lots of like items and individual pieces. It's not so much about the $$ for him, just clearing it ALL out.

Prices will vary greatly on what you have an actual condition. Make a list of your inventory and then check past sales here and elsewhere and you can kind of get a good ball park.