Hi Weedo.
Most of the manufacturers will have some info on the recomended size for weight. With all the top playboats, Fluid, Jackson, Pyranha, Bliss-stick..... you can't go to far wrong. For your weight I would say go for the medium sizes such as the Fluid Nemesis Medium. You might be able to fit in some of the small's of the playboats. If you do fit into a small version of say the Nemesis you will easily get tricks on flatwater, in a river feature you might flush a bit easier. I am a bit taller than you but not really heavier and paddle a medium Nemesis. The advantage of the slightly bigger/,more volume kayak is that you will get better pop for things like loops, you will also be a bit more retentive in holes/breaking waves.
My top recomendation will be the Fluid Nemesis but most of the new playboats are great. Other options I would recomend are the LL biscuit and the Pyranha molan.
Happy paddling