I don't have one, but I have always seen them being worn on the back with the straps crossed in an X over the chest. Because the fabric is wider and can be spread out, you can avoid "bionic boob." But I guess it would still flatten your chest and whether or not that bothers you is personal preference.
Has anyone done rucksack-style with a Frankenkozy? I like rucksack and that's part of why I prefer a regular MT.
What I do is to first tie my baby on the front
Then I untie the top straps
Move my baby to my hip (watchin out for the top straps not to get all twisted)
Then I slowly move him to my back
Than I arrange the top straps over my shoulders hanging towards the front
And then I tie the MeiTai
I can NEVER put him on my back without tieying him on the front first...
I've got 3 different versions of the back carry on there. The straps are the same as the Frankenkozy straps, just a bit skinnier.
Basically, you tie it on your waist first, then bend way over as you move baby onto your back. Grab the carrier with one hand (holding baby with the other), sliding it down the edge to grab one shoulder strap, then switch hands to get the other strap. Once you have a strap in both hands, you can let go of the baby as you pull the carrier up really fast. (Still bending over). Then place the straps over your boobs or whereever and tighten and knot.