I've made this point number of times, regarding spirals. They are well suited for some projects. I personally don't believe that one with straight lines or smooth curves is one of them. I can see the temptation to use a spiral for veining, but if you aren't used to them, I would suggest first cutting the line with a straight blade first, then following with a spiral to open it up.
The point about cutting sideways is a good one. Even though a spiral is designed to cut 360 degrees, that doesn't mean it cuts equally well in all directions. The saw and the wood both have something to do with that, as well. When using spirals and wanting to maintain maximum control, especially over a long line, I always cut in the traditional direction, pushing the wood straight into the blade, from the front.
Spirals do their best work on portraits, where there are many short, irregular lines. If I'm cutting a portrait and there are any long, smooth lines, I'll substitute a flat blade to cut those. That gives me the best results. IMHO the '57 Fairlane pattern is not well suited for spiral blades. I know guys who use a spiral for everything, even traditional fretwork, so it can be done. However, my personal opinion is that spirals and straight blades aren't intended to be used interchangeably.