1) I haven't found it to be a problem in following seas at all.  I do make sure I tie a strap around the telescoping swim latter to keep it from deploying
2) I have an Achilles of the same size.  The platform can carry the dink flipped on its side edge (when we're away from the boat we often store it there)-- but if we are heeling significantly the leeward end of the dink will start to drag in the water.   Obviously not an issue if motoring or not doing any heavy sailing, but if were going to weather in stiff breezes I either tow the dink or store it on the foredeck.
   The fabricator's website is here: stainlessoutfitters.com/products/marine/swim-platforms/; they pretty much make these to sketch with a variety of ladder and bracing options.   They probably still have the specs I gave them for ours, but probably would have to be altered for a C34.