This is a valid concern and one to sort out as you can. We are a heavier team and ride steel which has been fine for us. Titanium can be built to mimic steel with the diameters and wall thickness of the tubing used. Seven would be someone very well versed in building with titanium. Not sure where you live but a weekend trip to a dealer with a Seven might make sense. Where do you live you don't have that listed in your profile maybe someone on the forum could help.? Something else to consider if you are on Facebook the Tandem Bicycle group has over 2,000 people, someone near by you might have a Ti bike your could try. If you are anywhere drive-able to the East Coast the Tandems East Expo will have a couple of Sevens you could demo. That's scheduled for April 7 & 8, those are bikes are in their stock if I remember correctly so you could check them out at any time that at their shop.