In regard to smaller engine the most important elements are detergent, stabilizer, and possibly moisture control (if you are running a non-ethanol blended product).
Detergent wise: the highest specification in the market is the “Top Tier” specifications. Offered by most gas station (posted on...
#2 ULSD: has maximum cloud points during the winter seasons based on the average temperatures. Based on some testing done winter, I've seen cloud points as low as -15F and as high as +24F, it depends on the geographical location and refinery supplying the terminal. To your point about the...