Generally speaking, pine is a faster growing wood, and therefore will have fewer growth rings per inch. Cedar, in general, will have a tighter grain, which is stronger, and bends better. The cedar on my kayak has about 20 rings in a 3/4" strip... really tight-grained stuff. The pine accent strips had 1/2 or less the growth rings, and they did tend to break much eaisier than the cedar.

Please also note that pine is going to darken a whole lot when you put the epoxy on. It can even go almost yellow-orange. No big deal, but keep it in mind if doing accent strips, because once it's got epoxy on it the contrast may not be what you thought it would be.

As for weight, it will make a difference, but I can't tell you how much. Perhaps you should consider ordering strips. It does cost more, but you can get what you want, and it's already milled, so there's no waste.

Cheers,

Malcolm