I've already looked up here but so far most are only concerned with 3 or 4 mora suffixes or are overly specific. I'm looking for a generic rule I can apply for compound suffixes made up of 1 to 2 morae.

An example of what I want to predict would be か\んしゃ ＝＝＞かんしゃ\さい and け\いざい ＝＝＞ けいざいき\ぼ andしゅ\と＝＝＞しゅと\けん and せ\いび ＝＝＞ せいびほ\う.