Chubs I have 4 Devilbiss guns 1 is gravity an older GFG from the mid 80's its not HVLP
but what I like about Devilbiss is the parts availability & compatability with other models
(that was the case back then).
Needle wise on the GFG I have a .9 fluid tip & needle set & you could almost sign a
cheque with it I think it is too small.
I use a 1.4 for most gravity gun use, but being able to change set ups for different
viscosities ( rate of flow of a liquid, or how thin it is) this is what makes a good gun, you
can change parts & get parts.
There is recommendations on compressor size discussed here & there on the web but
again a manufacturer that has parts availability is key for me.
Different Air caps use different amounts of air so if your compressor can only put out a
lower amount of air maybe there is an Air cap to suit you, maybe in 12 months time
you will have other gear that uses more air & you can upgrade.
If you use air nailers & sanders & oil those tools NEVER use the same air line, a moisture
trap & regulator are good & not to expensive investments.
& YOU, Lacquer & there variants are not only FLAMABLE they are EXPLOSIVE stay SAFE
& protect those lungs hardwarwe stores don't sell spares, wear a suitable MASK.
On the cup size 125ml sounds a little on the small size but it would spray a body no prob
You can mix more lacquer ia a larger cup like this.
http://www.devilbisseu.com/en-gb/product/mc-1-k50
& filter it into the gun with this,
http://www.sagola.com/index.php?zon=car&pro=15&num=7
pics are for reference most auto supply stores should carry these.