Short note of my personal experience with fuel choices:
1. If your intake tuned length is very short, AND you're looking at spinning pretty fast, AND your cylinder head is aluminum, the 90% distillation temp is worth paying attention to. Lower 90% temp gasoline means it takes less time and heat to get vaporized. Higher 90% temps, in some engines will lead to white porcelains on your plugs, but black sooty exhaust and sometimes melted pistons as you try to figure it out. This can happen when all the fuel doesn't burn on time (gives a lean primary burn, followed by a long flame period at lower pressure...and into the exhaust, leaving the black soot).
2. In 2000 we tried running our 2 liter ModRoadster on a "heavy" fuel (high distillation temp and lots of BTU per unit). The car was running 102-103 mph, plugs were white, and the side of the body had 3 feet of soot trailing the exhaust outlet! We went back to the fuel truck, took out the heavy fuel (high 90% distillation temp), and put in the 118 octane with low 90% temp. We went straight back in line, changing nothing, and ran 183mph, leading to a 181 record that stood for some time.
3. 90% distillation temp is the temperature at which 90% of the initial volume is fully vaporized. I used to use Core Referee Lab, at Long Beach airport, for fuel testing (customer cars issues). They told me that 400-440 degree 90% distillation is about 1/2 and 1/2 gasoline and deisel (when folks goof up at the pump). If you need to run on the rich side, high 90% temps could give you trouble. The folks at the fuel trailer were very helpful in showing me the temp charts for the available fuels (last year and this year). I had no jetting difficulties, and both years bumped up records. The fuel I chose had the lowest distillation temps.
Lots of chemistry needs to happen in milliseconds. Hope this helps,
JimL