I've got a biopace on my old Schwinn Impact I'm converting to fixed for winter riding, and the tension changes just a little bit because they aren't perfectly ovalized, but sorta egg shaped.

The first time I took it off to clean I accidentally oriented it the wrong way with the cranks without realizing, I rode around thinking those things were the biggest POSs ever... now I like 'em.

And nice build, looks really fun to tear around on.