Or, you need a glider with an appropriately-sized control frame. IIRC, the 145, 165, and 185 Delta Wing Dreams all had the same size frames for commonality, which was fine for taller students, but a travesty for shorter ones. But if you do try the rearwire flare, you're gonna want some sort of padded bulldog clips to grip, so your hands don't slip. This is a very tricky technique that is obviated by having a proper size (small) control frame to start with. H4, Advanced Instructor, USHPA Life member since '74.
How will a smaller frame help with flare? The downtubes are just a fulcrun, our hands are on the upper half when flaring anyway. A shorter frame will help launching though.