If you are on a budget - I recommend a 12M waroo. You can use it in the water and the land. Its a bow kite so it has a pretty good range. I'm guessing at your weight you can ride it in like 15 knots to 28 knots??? Not really sure though.
As far as bow kites cutting down your quiver to one or two kites - yes, sort of. Sure you can ride your waroo in a huge wind range - but is it quality riding? You can still ride waroos when you are over powered - but its survival - or when its really light - then its a slog fest. I actually have a five kite quiver

But that covers everything pretty much. I live in the gorge and we get winds from 9 knots to 50 knots. Seriously. I have a 5, 7, 9, 11 waroo and a 16M vegas. I weigh 190. The 5m waroo only comes out when its over 40 knots. The 16M vegas is for when the wind is under 19 knots. And then the 7, 9, 11 are for everything in between. Of course I can get by with less kites, but I want quality kiting! Its a must.
anyways - back to the 12M waroo. Its got a pretty big wind range - you can find 06 12M waroos on the cheap - check out ebay. It can be used on the water and land.