I've found no difference in the speed of trace based only on EO v/s FO. It all depends on the chemical components and how they interact with the lye. EO's of clove and cinnamon move like lightning but so can floral FO's. I always choose a new EO/FO and how I'm going to use it (or if I am) based on research into it. I always read the description & reviews on the website (if they have them) and go to the Fragrance Oil Review Chart on SMF.
The chart can be found as a sticky under "Fragrance Oils/Fragrance Reviews". Here's the link:
Spicy and floral eo's can speed trace. Cinnamon and clove are notorious speeders. I have a ylang ylang that goes to soap on a stick in a matter of seconds and a lavender that speeds to quick to do colors. Some herbals eo's such as thyme will also speed trace