The question about using other paints ie Acrylics is not a stupid one. I would suggest using Acrylics or even oils on the basis that the "good old Humbrol enamel colours" contain a thining agent which with constant exposure is bad to the health. A water based or water soluable paint would be much better, they are easier to work with and cheaper.
The Tamiya paints, the Acrylics are perfectly safe, they are water soluable but for diorama basing a bit expensive. Normal Acrylic wall paints will do, for the price of a Tamiya colour you can get 1/2 a ltr of wall paint at the local hardware shop, and some of these hardware shop acrylics are so good that they are usefull for actually painting the large areas on the figures, ie Horses.
I still have Humbrol paints, some 30 + years old, they are still usable but boy!! when I have used them I feel a bit "stoned" afterwards. Not good
They have their uses and some people prefer them...not me though, if I want to get a bit "misty" in my head red wine is the one for me (or the second glue
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There´s a lot of different paints and opinions on thier merits etc here;
http://www.bennosfigures.com/forum/viewtopic.php?t=4420