Reading of １/一 with less common counters

So with the usual counters like 回,年,本,冊 and others, a preceding 一 is read with the onyomi of 「いち/いっ」, but I’m often not sure how to read it when loanwords are used as counters. I remember hearing １クラス (one class) read as 「ひとくらす」, would this case be the same resulting in 「ひとついーと」?

by Fobias89