The /ʊ/ vowel is spelled <oo>, <u>, and <oul> in should. The /ɪə/ diphthong is spelled <eer>, <ear> or <eir> in weird.
This is a contrast between a short vowel and a diphthong, widely separated in the mouth. It creates no problems.
The density figure is 0.31%. The set makes 6 semantic contrasts giving a loading of 100%, though that is insignificant in such a short list.
good geared pud peered should sheared stood steered wood weird woody weirdie
John Higgins, Shaftesbury, December 2009