I am toying with the idea of asking the seller if he might show me the scope under clear, dark skies, but the weather lately has been back and forth, and I feel as though if I go to see the scope a second time, I am almost committing to buying it.
Absolutely get this idea out of your head.
You are about to fork over a pile of money in a cash transaction. No warranty. No guarantee. You should be given a full demonstration at night, and if the seller hems and haws about this, walk away. Any legitimate seller should actually enjoy showing you the scope.