I have used Conti Gatorskins wire bead tires for many years and they work well in terms of durability and flats. One reason I started using them was many years ago I tried a folding tire (Conti I think) and it blew off the rim several times. Not wanting to take any chances I went with the wire bead. In retrospect I think the tire blow off was due to due to the tire / rim combo.
Recently I have been wanting something that is more of a racing tire.
I put a Rubino Pro 25c on the rear. It is holding up pretty well but I don't care for the rough textured tread. So I ordered some Rubino Pro Slicks and waiting for them to come. In the mean time I had tried a Conti 4000s on my single earlier this year. The 4000s had a lot of things going for it. Low rolling resistance, resistance to cuts, durability, its tough as hell. But on my single the ride was harsh and I like Michelin Pro3 tires much better. Today I decided to try the 4000s on the front of the tandem even though I would normally not use a 23c tire on the tandem. Well I was surprised. On the tandem this tire felt smooth and much nicer than the Gatorskin. Steering felt more nimble . The 23c was not a problem at all I did not feel the tire was overloaded or compressing too much. So now I am thinking 23 on the front, 25 on the rear. I may try a 4000s on the rear but will give the Rubino slicks a try first. I know Pro3 has been mentioned by a few here, but I wouldn't feel comfortable with that on tandem because of fast wear and the pressure rating is not very high.