Haynes makes a good book on welding titled: Haynes TECHBOOK WELDING MANUAL. It is great for beginners and also for those who know how to weld. It talks about all forms of welding, but has a good page or two on wire selection, and mentions a wire made by L-tec called Easy Grind. I haven't used it but have friends who swear by it for body work. I too tried using the flux core stuff first, just because of the initial expense of the C-25 bottle. But you usually do start with oysters and work your way to caviar. Man the gas is smooth, no spatter to grind, no slag to clean. That's strange that everyone tells you flux core is better, I've never met anybody that has preferred it unless they are welding a steel fence in the middle of a pasture in a 100mph wind! Take any measures possible to create a wind break and go gas.
1956 Chev 150 2dr sedan 302ci
1965 Chev Malibu 2dr hdtp 496ci
1967 Chev Camaro 327ci