Well the 109b is typical Grob,
heavy on the rudder and you need a little bit taildragger experience.
When the heavy T-tail starts moving, you have to be ready to catch it.
The Schemp-Hirth airbrakes are very effective with no negative effects on the trim and allow very steep descents.
Take off performance with the standard Grob engine (87 HP) ist not the best, with a 2.4 L Limbach Turbo (Korff conversion to 130 up to 140 HP) its a real fun airplane suitable for glider towing.
The laminar profile of the 109b has no problems with rain (the 109A is very rain sensitive!), but you lose vison out of the cockpit on approach or in the flare, because the water will stand on the canopy. (The remedy: Fly a fast approach (150 to 170 km/h) and brake with the airbrakes short of touchdown).
With more than 6 feet you will get a problem with head space.
Greetings from Germany
who flew the normal G109b and still flies the Korff Grob from a 500 meter gras strip.
PS: Interesting links:
Grob G109 Handling Notes