The Hydro is an intermediate kite, which is great for beginners and little advanced riders. Easier to restart and good handling.
The Mach1 is an high aspect ratio kite, which is faster and has more lift for jumping. The Hydro 11 has a surface area of 15 sqm, the Mach 1 12.1 has 12.1 sqm.
Concidering your weight and the winds you want to ride in, you should get a kite of about 14-16 sqm. This size is not good for beginners, better is 12 sqm, but i won't get you going in light winds, also if you want a smaller board, the bigger kite would do.
And since you already ride and make fast progress go for the F-One 15.1. Greta kite, fast and good lift. If you have problems relaunching, attach a 5th line and the problem is gone until you don't drop it many times anymore.
Hope that helped.
If you get confused with sizes like projected and surface (total) area, have a look at http://www.kiteproshop.com
, they have many brands with their sizes and the surface area.
Or maybe anyone knows a tab with all sizes?