Tyre size choices

[Dstan0710]

I’m looking at a set of wheels in 15inch 5.5 for my T25 and need advice on tyre size for not rubbing and also to look right. I gather I’m looking for 175 or 185s but it’s the ratio I’m not sure on. That’s the depth of the tyre from the rim. Please could someone advise what they have found works. Also if from the info below you can tell of if I will need spacers.
Thanks in advance
Width 5.5
PCD 5/112
Offset ET+20
Back Space 4.04