yes the 7778 is the all metal body model, It is VERY nice
I'm a Signman (Commerical Artist/ hand lettering type)...One of the old time Sign painters. I use about a dozen vaious air brushes on an almost daily basis. most det up with different needle/ nozzle combinations for different spray pattens. Others with different size cups and media bottles depending of the size of the job.
One of the very nice things about the airbrush is just about any media than can be thinned can be airbrushed.
Just so you know, acrylic enamels, and regular hobby enamels are oil based. Keep in mind any media that thins with any product orther then water is considered an "Oil based" media.
Some waterbased acrylics contain a material called "Smoothie" (a fisheye preventative) that will react with straight water based paints making a sort of gel.... not a good thing.
You should not be afraid of oik based materials, they just require a little more clean-up than water based paints. Simply keep in mind once you have used an airbrush with oil based paints, it will need to remain a oil or acrylic based airbrush. Do not attempt to cleans it for used with water based media. If you do your finsih will have an oil blemish called a Fisheye. At home I have two airbrush set ups one for oils the other for waterbased. It's easy to keep the two seperate by painting the handles a specific color and/or wraping tape or other identifing marks on the water brushes. As a matter of fact my Aztak is used only for oil based media.
I'm not sure how many here would be familiar with "one shot" sign lettering enamels but they are a constant use item for me.
One-Shot has some really great colors and pearlescent colors that look great on Mod-Rocs. They also contain lead so caution is required in its use.
Pactra, testors, True scale and just about any of the hobby model paints and dopes can be used. I also use a good be of Richart watercolors and loads of tempra dry pigments to make my own colors. I've even melted some prisma color pencils to get a specific rust color I was looking for... In a word.. you can use any thing that you like. just keep the water and oil seperated
hope this helps
One trick that can reduce the clean-up time for waterbased airbrushing, is to keep the airbrush submerged in a water or thinner bath between cleanings. This is not ment to say you can leave the brush uncleaned for and indifinent amount of time, but it you are in the middle of a project and need a day or two to get back to a specific color or spray pattern just keep the brush settings as they are and temporarally soak the brush in what ever thinner is used with that media.
You may want to add a second Passche or Badger airbrush set up to your modeling tools to keep all your options open.
Hope this helps