There's also a tandem subforum, check in there when you get a chance.
On my tandem, I use 700x32 at 100 psi, gives a fairly cushy ride.
Advice/cautions: Get familiar with the brakes before hitting any long steep hills. (Is that a drum brake/drag brake on the rear?) Watch the gearing going UP a steep hill- doesn't look to be geared too low.
It took me about 1,000 miles before the tandem didn't feel "weird".
When I first started, I could stand, or stoker could stand, but not real comfortable either way. But if we both stood, hey, no problem, although it seemed like it'd be harder.
When you stand and pedal while stoker stays seated, you have to watch, as you can flop the bike to one side or the other and it won't flop back!
It may be helpful to communicate when you're going to coast. "Coasting!"
It's helpful to holler "bump" when you see one coming up, the stoker can't see them.
I was riding with a tandem couple one time and the stoker was saying "6...5...4..." She saw me looking and said "Oh, it's just something we do..." Later, I found out she was telling the captain what gear he was in, he can't see the rear sprocket.