How much paint thinner do i use?

You can clean the pipettes by drawing thinner into them and squirting it out. If the paint pigment is allowed to settle, the thinner can be used for cleaning purposes a number of times again.

Straws are a good alternative as suggested and they are free!

I just use disposible plastic straws. I cut them in thirds and hold a finger over one end. I can transfer quite a bit of paint this way and I can count the drops to get a specific thinner/paint ratio. If you need to move a lot of paint, then go with the afore mentioned pipettes. (But they can get pricey over time)

Disposable plastic pipettes. The link below is merely to show you what they look like. Evil Bay is a good place to find them...

http://www.labdepotinc.com/Category_Details~id~216.aspx

What do you use to get the paint out of those little tins, i tried pouring some into a spoon and that was a disaster. I ended up wasting paint.

I tend to use 60% paint, 40% thinner. Best way is to start with that and test it on a scrap model/plastic sheet. Don't try cardboard as it absorbs liquids and can give you a bad test result.

If too thin, add some paint, if too thick, add some thinner. Often a few drops will make a difference so don't over do it.

Regradless of the instructions, use an amount of thinner that works...Airbrushing has three simple variables (Air Pressure / Paint Viscosity / Shooting Distance)

Paint Viscosity has to do with the type of paint and how much thinner you use. As you "tweak" the variables you will get different results. Trail and error is the best way to find what works for the specific result you are looking for.

I don't use humbrol enamels, but some other folks might be able to give you a baseline starting point.

Good Luck.