Magnus, with a LAK17C you won't be able to take off safely from Montricher, especially not to the northeast. I wouldn't go for less than 50 hp, and that leaves you with Ventus 2CM, DG800, Antares 20E or ASH26E with the Schleicher prop.

Bert
Ventus cM "TW"
working in Lausanne, flying in Bex