broke my rib as well
used a seat harness for ages
tried waist's but they ride up and hammer my bad rib
tried the ride engine, but the rope broke way out back
that was fun...not
thought of the dynabar, but it has issues
created a solution which has worked pretty well so far
used it in mexico, hawaii, japan and australia
here's the deal:
go to a marine shop
buy two stainless steel D rings, one O ring, and rope with a 'significant' breaking strain
cut off the spreader bar on a seat harness
using seat harness' side adjusting straps, attach D rings on harness' left and right sides
use rope to mimic spreader bar between D rings
before tying off, slip O ring on the rope
done, you're good to go
when setting up before launch...
pop the quick release
take the now-open chicken loop and thread it through O ring
reset the quick release
attach leash
enjoy your kiting
note: the cabrinha system is a bit tricky
the QR release does not open up the chicken loop as with other bar systems
so you have to make some adjustments
like thread the spreader rope through cab's chicken loop
then retie the rope to your D ring
test your gear before you use it
know how to release
know how to how to how to whatever
this works for me
it may not for you
good luck