TLD have by far the best fit for small heeds. Mrs Legend’s always had trouble getting helmets to fit properly, Bell Bellistic/Rhythm Pro used to be a great option but discontinued a couple of years ago. Unfortunately TLDs obviously aren’t the cheapest, but there’s often a deal or two to be found. D2 works well, I’m reliably informed that D3 is even better.
Anotherstan, are you sure the fit’s that good? Many of the girls that race Diva Descent turned out to have poorly fitting helmets when they compared their own against a Troy Lee XS
EDIT: 661’s site says that the Comp and Evo are the same size. Mrs L had an Evo briefly and it was definitely bigger than an XS Troy Lee D2