HVLP Spray gun tip

At least the 1.4mm. What types of paint would you be spraying? Oil base and heavy primer won't spray well (or at all) through a 1.4 or smaller. I think thats the tip I use in my clear gun and its near max on the fluid needle. 1.6  or even 1.8 would be ideal for heavier paints. 1mm and smaller would be a small touch-up gun.

All of those tips sizes are small for the materials I use but I am only 1/3 step over beginner. I suggest that you decide which material you ar going to use and go with the "P" sheet recomendations from the Mfg. If your tip size is off a small amount you can adjust the reduction a small amount and the paint will go down nice, I do this all the time but you do not want to vary a lot from the P sheet especialy while learning. Like a lot of other things painting often gets beat to death on forums like this because everyone, including me has their own little favorite tips and techniques and it will end up confusing the issue for the newbie.  Luckily we have available to us what are called "P" sheets, the directions for correct application from each manufacturer (at least the quality ones) The P sheets from PPG Ditzler (just happens to be what I use) are very easy to digest. My recomendation is despite all the tips you will read and hear about is that you purchase ALL of your material from the same supplier then mix and apply the materials as recomended on the "P" sheet and use them at the reccomended temp in the recomended equipment. You will then have a very nice looking paint job to show off.  Nothing will cost you more time and money than having to do it twice which can easily happen when guessing or when trying  things outside of P sheet recomendations, been there, done that also.  Good luck.