Aliasing sakuma_eiko <-> sakuma_hideko.
Reason: According to the Pixiv Encyclopedia (http://dic.pixiv.net/a/%E4%BD%90%E4%B9%85%E9%96%93%E8%8B%B1%E5%AD%90 ), "Hideko" is the proper pronunciation of her name (佐久間英子) rather than "Eiko," as described below (full translation is welcome):
ちなみに名前の読みは「えいこ」又は「ひでこ」等が考えられるが、本記事では元ネタ(佐久間正英)に従い、「ひでこ」の読みを採用している。
However, NicoNico Douga's encyclopedia (http://dic.nicovideo.jp/a/%E4%BD%90%E4%B9%85%E9%96%93%E8%8B%B1%E5%AD%90 ) still uses "Eiko."
With no other sources concering pronunciation, this can go either way depending on your discretion.
Updated by jxh2154