Yes straight from the bottle, no diluting. You dont really want to go over the same area more than once (unlike some bigger scales) . The good news is that a bottle will last a long time when painting 6mm figures!

Vallejo are really great for 6mm. Sometimes you have to dilute them a bit, they tend to get drier in time (like all colours). But you have to stir the colours up before use - easiest way is to put someting heavy into the bottle, like a screw or somesting like that. Shaking the bottle afterwards ( (the closed bottle - once I a forgot that, and i can't recommend it...)  will mix the colour thoroughly.

I always add a drop of mixing medium, mixing medium is a transparent resin base designed to thin or dilute your paint without changing the flow and viscosity of the Acrylic or Metallic, I can't paint without iot now.

Vallejo are excellent paints, as long as you make sure the bottles are well shaken before you use them. I recommend buying some 6mm stainless steel ball bearings to use as agitators. 316 marine grade will not rust in the paint.

I generally use them neat from the bottle, but they can stand a little dilution with water or mixing medium depending on what you want to do with them.

I agree that when painting my figures, I only want to use one coat per colour as well. Even with the larger scales I'm looking for something that looks ok, not after any prizes.

6mm is perfect for those who want to field impressive numbers of figures on a table, they can be painted quite quickly and simply and the main visual impact is from the massed ranks rather than individually painted bootlaces.

For those who are really into painting individual buttons, bootlaces and blending colours, then perhaps 6mm isn't the right scale, 28mm+ will give you more jollies per figure.

There is plenty of detail in Baccus figures to paint if you want to, but neither my hands or my eyes are steady enough. Command models do get extra time spent on them, but that's about it.

80% of my paints are Vallejo. I use them straight out of the bottle onto a painting palette. For 6mm they will last and last.

Gosh, how peculiar! I can't get them to flow at all unless I dilute with water. On 6mm I always use a white primer, then diluted Vallejo, then sepia magic wash.

Black primer. Basecoat, highlight, wash of some kind, either sepia, umber or a colour tone (Warlord), blue, red etc  depending on the dominant colour. For WWII Military Shader from Warlord Job done.

I use a mix of paints I've picked up over the years, including Vallejo, and dillute all of them in use.  Note that you're not looking to dillute to the point of a wash, just enough to get the paint to flow a little easier.

FMB

Use Vallejo almost exclusively. Paint black base coat and then work my way up the figures. Paint slightly lighter colors then larger scales. I work on about fifty at a time. Just started 6mm a couple of months ago and love them.

Shake them hard  for a bit and roll them to mix them well.  I don't usually dilute them in water, but I do wet the brush a bit while painting to get the consistancy I want. For 6mm I don't dilute much at all.   I have run out of a few vallejo colors over the years, but they last years if capped.  I still have the first German Fieldgrau bottle I bought in 2002 and have painted many armies with it.  Also, clean the nozzle before capping.  Most of my paint loss has been when nozzle crud created a gap that let the paint dry out.