I would go with Nigrescens which would continue the upright theme at the back of your bed, it would be a bit like a family tree as RS came from KR which came from Nigrescens.

I really like the tall uprights. I like to see their " legs" so I wouldn't crowd them too much with the mediums in front.

Denis

Just looked it up and it's a beautiful hosta, love the color. Seems hard to find. Deff adding this to the list of wants.

You could have a classic garden by adding June, Neptune, First Frost, and some flashy yellow, like Dancing Queen or On Stage.
Kathy

El Nino is always nice; listed as a medium, whatever that means, exactly... : )

Don B.