Discovered this site & forum – so glad I found it!
My reply to favorite double white of those already mentioned is: Mother’s Choice
In addition, we’re also growing Mary E. Nicholls, White Wicker & Yang Fei Chu Yu which to experts may not completely meet requirements of PURE white. Nonetheless, are young garden is graced by their presence.
It will be quite a while before we can fully appreciate any of the cultivars we are growing here, as our garden renovation & design is really rather new.
Best Regards from Southern Finland!