The /ʊ/ vowel is spelled <oo>, <u>, and <oul> in should. The /eə/ diphthong is spelled <are> or <air>.
This is a contrast between a short vowel and a diphthong, widely separated in the mouth. It creates no problems.
The density figure is 0.83%. The set makes 8 semantic contrasts giving a loading of 100%, though that is insignificant in such a short list.
bully barely could cared fully fairly hood hared pud paired should shared stood stared wood wared