Roger brought up a good point about sail size, as I was think that in the long run you're going to be more versatile on a larger sail, like maybe a 7.5 or 8.0. However, while you're starting out, a 6.0 would be much easier to develop the basic sail handling skills. The real downside with the 6.0 is that it's quite doubtful that you would able to plane in the 10-15 knot range. Yet, for your size, a 6.0 would ultimately be a good sail in stronger wind.
The thing that you'll find out sooner or later is that one usually needs more than a single sail to get the most out of the sport. Because of this, it's quite important to plan your procurement so that the equipment you buy will cover a few bases and offer some flexibility overall. Really, this is most critical regarding your mast and boom. While you may elect to think about adding sails at a later date, it would be a good idea investigate what your future options might be. This is fairly straight forward, as sail specifications (luff and boom lengths) are readily available online, and it's very likely that your retailer can assist you in this so that you understand your potential. Also, be sure to note the adjustable range of the boom, and keep in mind that most booms, particularly aluminum ones, get more questionable (less stiff) when extended to the extreme, thereby allowing the draft in the sail to move around too much and creating instability.
If you can swing it up front, I would recommend buying two sails, like the 6.0 and a 7.5 or 8.0. Another thing I think it's wise to consider is whether the 6.0 would have an adjustable top allowing for the use of a longer mast. To support the larger sail, it's very likely that a 460cm mast will be needed, and it would be a better value overall than a 430. The cost variance between the two sizes is minimal. Being a heavier sailor, I don't think that the larger mast will be a liability, and it makes much more sense than trying to make a 430cm mast work in a 7.5 or larger sail.