3．In choice of instruments，it is better...satisfaction sake：

该句的主干是it is better to choose men...than those...。

that are like to do that...the success是定语从句，修饰men of a plainer sort；其中to do that...them和to report…the success是不定式短语并列作表语。这里的like即现代英语中的likely。

that is committed to them是定语从句，修饰后面的that。

that are cunning…sake是定语从句，修饰those。

不定式短语to grace themselves作目的状语。

grace在这里作动词，意思是“给…以荣耀或光彩”。例如：The occasion was graced by the presence of the Queen．女王驾临使场面增辉。

for...sake或for sake of的意思是“为…的缘故”。例如：for brevity's sake为了简略起见。