It's personal preference. My daily is the shorter rindeleder on the middle left - I eventually cut the bottom D-ring out, scrapped the linen side and I like it MUCH better.

The leather is nice, but if I had to choose again I would definitely get the longest one I could find (either of the right two). But that's because I'm a slow stropper and like the handicap of the longer strop, it saves me time. I had a leathershop make up two 2' strops out of a belt and I love them. But the leather's kind of slick so I use them for pastes.

I wouldn't mess up an expensive dovo strop with paste. Except for the yellow 'tenderizer' paste, I think it's just animal fat. I tried their green paste and don't like it. When it's time for the green paste I just hone the blade. Get the industrial abrasive pastes (the .5 micron / 1 micron) that come in the syringe, put that on a cheap secondary strop, use the dovo for daily stropping and you should be set.

That's what works best for me. But you can pick whichever, like AFdavis said, any dovo strop works great.