I use marathon + tires on my trike, the fronts are 20" and the rear is 26", if I remember correctly they are all 1.75 (or at least the rear is). They are not perhaps the fastest tire but I don't get flats/punctures. I switched from a Schwalbe Kojac 35-559 rear on my Velomobile to a 35-559 Marathon + due to a sidewall blowout from a Kojac. A rear blowout can be (and was catastrophic in my case in the Velomobile) on a tadpole configuration (2 wheels front, 1 rear).

The Marathon + is definitely slower (but have adjusted) and have not had a flat since installing it with now close to 7000 miles. It is starting to wear down some and when I replace it I will install another Marathon + for piece of mind, confidence, and insurance to have high chances of NOT having a rear flat. For the Velomobile I use Schwalbe Durano 28-406 front tires with not many flats, it is far less dramatic having a front flat compared to a rear flat.

EDIT: The biggest thing I see with the Marathon + is that the rotating mass is heavier causing a slower speed and more effort to climb hills, flats and down hills are only slightly slower than using the lighter weight Kojac.