*Disclaimer: I sell all of these things...
Lots of good advice here. I'm also 230 lbs, been kiting a long time, and learned up on lakes in Wisconsin (I lived in Madison). For big dudes like us, getting proper sizing advice is difficult most of the time. People are always telling you that big boards can't be fun, you'll outgrow them, etc...I don't find that to be true. I use a Litewave Wing 165 most of the time here in Florida, though I like it when I can shift to something smaller. My step down board, when it's windier, is a Mako 150. They ride smaller, closer to a 144/145, but are so much fun. But I seldom ride anything smaller than 141...it just takes too much power for me at my weight.
As far as the kite sizing goes, I generally advocate for a 17, 12, 9 combo. Could you add other sizes? Sure, but those 3 sizes can cover most wind ranges that the average kiter will experience (especially if you're in Wisconsin or Florida). I'm only just now going to add a 7m kite to my own quiver b/c I had ONE session last year where I flew an 8 in 40-50 mph, and would've been powered just fine on a 7.
Think of different kite sizes and boards like tools in your toolbox. Hammers are fun, but sometimes you need a screwdriver. Get them at whatever timeframe you can afford to, but have a plan of what you're going to need so that you don't end up with kites/boards that don't fit your usage.
I'd go with that 17 first, since that's likely the wind you'll see the most where you plan to ride. Getting a kite that's not big enough will just frustrate the crap out of you, though generally any time on the water getting used to flying the kite is good. Good luck and welcome to kiteboarding!