Although I'm not tandem experienced, I am 1 1/2 yrs recumbent experienced after riding a df for 6 months. Depending on how much saddle time you can put in, it might take you some months to become comfortable and confident in your new muscle skills, so don't expect big changes right away, but it's interesting and you will notice certain routes and times and your physical effort will progress. I've got 6% and 9% grades on my daily commute so it was no fun. I can't tell if it kept me from getting my 'bent muscles in shape sooner accelerated my conditioning involuntarily.
Could you share why you picked the bike you did? I have no preference, just curiousity.
Leo H.
Sun Valley, NV