I've recently bought a tandem - a Dawes Two-Way Street LadyBack - for the wife and I to have some fun on. I am a very keen road cyclist while she is not very confident on a bike at all. After a few weeks we're having great fun on it so far and have been increasing the distance of our rides steadily (longest is 40km so far).
The tyres currently on it are 700x38 Ritchey Megabite's - which kinda look like very worn mountain bike tyres. I'm looking to get some new tyres on it which will hopefully give us a bit of extra speed without sacrificing puncture resistance or handling/comfort too much. We're looking to hopefully do a 100km in a few weeks to visit some friends and possibly a little mini tour to holand on it later in the year so getting something which rolls reasonably well would be a plus. That said it's not a road bike so we'll never be riding at 20mph! We'll mainly be riding on roads with i guess the odd mud packed trail or canal path thrown in.
I've read about Schwabe Marathon Plus's being great for puncture resistance and they look reasonably smooth (ie not too nobbily). Assuming this is a good choice (feel free to suggest others) what size should I go for? My wife and I are reasonably small (75kg and 50kg) however i've only ever used the 23cs on my road bike and don't know whats the norm on this sort of tandem!
Any help greatly appreciated.