Know what you mean about C'dale ride being 'a little harsh'!
Two years before there was a C'dale tandem (mid-80s) on the market we were test riding/evaluating one of the two C'dale tandem prototype for 3 months for the company.
Stoker Kay did compalin about the extreme harshness of the ride in the stoker seat. C'dale decided to market the tandem as a 'frameset only' but did not do too well until they started to sell fully-built up tandems . . . and oh yes, the suspension seatpost was re-introduced shortly after that!
To be fair, there are all kinds of suspension seatposts out there, and C'dale does not exactly offer the best one.
Off all the rear suspension ones we've tested, the original Thudbuster (parallelogram) stands out; however Kay was even happier with the old c/f beam Softride on a Burley.
C/f is a totally different ride . . . it'll provide both performance and comfort.
The fall is the best time to order a new tandem; catch the builder when things have slowed down a bit. In the spring everybody wants a new bike and then there are delays/backlogs.
Start your search early so you can weigh all pros/cons.
Good luck and pedal on TWOgether!
Rudy and kay/zonatandem