My opinion....... I build on the straightest axis as well, and have had no trouble.
I have read a fair amount about spine orientation, and finding the spine. I have come to the conclusion that it's not really such a big deal as I originally thought. Many builders go for the straightest axis and don't worry too much about the spine, and that's how I've built my last four rods. all seem to be just fine. The only time I get real picky about it is if I am restoring an older rod. In that case I am very meticulous about keeping all the alignments and locations exactly as they were................ModocDan