This whole discussion comes down to deflection of the tire and increased rolling resistance. You have X lbs. of load and X lbs. of pressure in the tire. At 120 psi (pounds per square inch) you will have a 3.33 square inch contact patch with a 400 pound load. That size contact patch will not change if you have a 23 or a 32 tire - the size of the contact patch stays the same. Consequently, with a narrower tire you have a long narrow contact patch while with a wider tire you have a shorter and wider contact patch. (Some people try and compensate for this by increasing the tire pressure, thereby decreasing the size of the contact patch - but this does increase the potential for blowouts and reduces comfort.) No big deal until you consider deflection. With the longer/narrow contact patch the tire deflects more, flat against the road instead of round thereby increasing the rolling resistance. All the crap you will ever read or hear about "fast" tires comes from the "super special secret sauce compound" that a tire company is using to reduce rolling resistance.

Putting a narrow tire from a single bike on a tandem increases your rolling resistance and decreases you safety and comfort.

Narrow tires weigh less and therefore have an advantage in acceleration, etc. and are the tire of choice for a 135 lbs. dripping wet pro on the lightest weight bike available but the increased rolling resistance with that same tire on a tandem overwhelms any weight benefit according to the studies performed by Bicycle Quarterly.

In my opinion, the best tandem riders can do is look for a tire size that minimizes deflection and rotating weight for their size team.