Well written Paul. I was a die hard flat blade user for probably the first 15 years of scrolling, tried spirals a lot of years ago and had no luck with them. Finally met another scroller who used only used spirals and he helped me learn to use them properly. Took a little getting used to, but now, like you, I often used both flats and spirals on the same project. It is what the cut and pattern calls for as to what blade I use. Still prefer flats for cleaner cuts though.
Jeff