He always drags out discussions by making quibbles.
Stop that pointless arguing and let's get to the main topic.
屁理屈 is more colloquial and dismissive, often meaning 'bullshit argument' or 'specious reasoning', while 小理屈 is slightly more neutral and focuses on triviality.
理屈 is the general word for 'logic' or 'reasoning'; 小理屈 adds the nuance of being petty or trivial.
Standard kanji spelling.
Variant using 窟 instead of 屈; less common.
Compound of 小 (small, petty) and 理屈 (logic, reasoning). The exact historical derivation is uncertain, but the word transparently means 'petty logic'.