dritar said:Does this also apply to curled seiza? It's the only one that I can't get heels together (if I do the stretch becomes only on the big toes/ball of feet).
A little gap is acceptable in order to even out the stretch. The main point in the heels together instruction is as Alex mentioned, the ankles will roll to avoid stretching. If your alignment is correct a small gap is acceptable, no heels rolling out.