Hmm, I assume the K1s will be K1 marathon racers, so fast but not particularly stable (ask the submersible Jamie :D). The tourer will be sit in, but probably have a huge cockpit so won't feel constricting, will go quite fast and may have a rudder or skeg to help you go in a straight line.
The GP kayaks are likely to be dancers or falchions or similar. Personally I would go for that. It would do 90% of what a tourer will do, but you can take it out on the sea or river or anything else you fancy (hence the name). The cockpits tend to be smaller so worth practicing getting in and out til you're confident.