Hi Kiwi Ben,
At 100 kilos, the Hyper 125 would most likely be better for you.
All the Hypersonics "shared" the same bottom/planing surface configuration in a particular year model.
First one to come out in 2003 was the Hyper 105, but many larger/heavier sailors felt the volume was too low, and had issues getting the 105 ltr Hyper going. So later in the model year Starboard came out with the 125 liter. The outline and bottom shapes were the same, the 125 was simply "thicker" (they added the extra volume to the top of the board vs the bottom or width).
In the second year, 2004, I had all 3 Hypersonics (133/111/96 liters).
The bottom shapes were identical, and the 133 and 111 had identical outline shapes.
The Hyper 96 was very slightly narrower at the tail.
At 100 kg. you can probably get the Hyper 111 going, but you are going to be very near the semi-sinker threshold with a rig as large as 9.0 m2.
Not to discourage you, but getting acquainted with and learning to "love" the Hypersonics was not real easy for alot of sailors.
You either loved them, or hated them.
If you want a challenge, pick up the Hyper 111 for $400 and let us know how you get along with it.