Definately turn the pilot light out! Don't assume that a home made booth will keep the fumes away from the open flame. Also keep in mind that solvent fumes are heavy, the will pool up around the floor level, and you may not realize the fumes are as bad as they are. In my area, the recomended minimum distance to any source of ignition is 25 feet or more. Dont forget other sources of ignition, auto door openers, light switches etc. Your choice of exhaust fan should be one of aluminum or with an aluminum prop or blade. (sparkproof) It should also have a TEFC motor, a open case furnace motor is not advisable.
Some people say its overkill, but you only need one thing to go wrong to find out the hard way. Use a pleated style filter if you go with store bought filters, they work much better and can be vacuumed for longer life. I use them on my airbrush booth.