SYP or SPF for rafters?

[Erin]

Both are fine from the engineering standpoint.
But, as we all know, SYP has a tendency to curl up like bananas.  However, we're going to put them up within a few days of purchase so they might not get as much of a chance.  They cost 15% less than SPF.

Or should I go with SPF because the additional cost is worth the saved hassle?

[PEG688]

 SPF twists quickly as well, I'd go with the SYP over SPF , unless straight DF was available in your area.

Around here in Western Washington they dropped SPF about 5 years ago , DF came down in price or the SPF mixed species when up , the bottom line is the DF lumber came to a price balance with SPF and the local yards just started carrying DF.