That's how I currently do it brother; weight and weight alone. From time to time, someone will need some cash and ask me to "loan" them some greenbacks, offering to let me "hold" pm's for collateral. Often times, they will not be able to pay me back in a timely manner. When I say timely, I will give a friend a year to pay me back, after which I am at my discretion as far as doing a reverse transaction.
That is how I got my collection of slabbed quarters and dimes. I will give you weight and weight alone; no premium.
I have a couple of buddies that are heavily in to numismatics, but who also buy sovereign silver/gold issues like Kooks or ASE's. That said, one friend boasts that he has a collection worth over a hundred grand, but he'll admit it is only eight or nine percent of that in weight. When I ask him who he'll sell it to when TSHTF he just shrugs.