Thanks for your view. My girlfriend isn't a skilled Windsurfer yet. The board must support slowly executed tacks in choppy water - I don't know how stable the short AtomIQ is. My girlfriend can't jibe yet in planing conditions - she just knows the technique for light wind jibe. But we will check all the options - the AtomIQ 100/110 as well.
In September we will spend 2 weeks at a place, where RRD Firemove (e.g. 112Lts: 238x74cm or 102Lts: 238x68 cm) are available at the rental station. Maybe this will give as an idea what size or kind of board to choose ... for next year.