They were modeled in Silo.  I think I'll try going back to an early state of build, when the boot was low poly and start from that.  I zeroed Rex out and exported him and now have his feet and lower legs in the Silo scene.

     It might be worthwhile for me to look at a few other auto-conversions (I ran conversions for Alyson2 and Cookie), and see if they survived relatively intact.  Fine details like the eyelets and lacing really show it if there is much distortion.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5