tig torch options and dinse connector adapter 3/8 size.

i have a 140ST im looking at getting a smaller tig torch, the one that came with the welder is kind of bulky, i think i would really like a smaller one.

so i was looking at the wp9 style or something thinner and or smaller than the one that came with the 140st.
now i have not done much tigging at all and the set-up i have is pretty basic one with no fancy stuff so...

1. now is there any rhyme or reason to the sizing and numbers of all these different style/size torches?

2. any one have a recommended brand in the size or similar size torch for me, also it needs to be air cooled and have a gas valve on it. im looking for something on the cheaper side and also looking for the consumables that would work for that torch?

3. any recommended dense connector adapter?