First of all, yes ET is the time it takes from when the light turns green to when you cross the finish line. 60 ft times are just that. They are a good representation of how well you are launching. On street cars with street tires, anything in the 1.8 - 1.9 second range is good.
You should be able to do fine with the stock clutch provided you don't abuse it. No clutch will hold up to repeated abuse. Somewhere between riding the clutch too much and dumping the clutch is a sweet spot where you will launch like a rocket, and not abuse your clutch. It's different for everyone, so you'll have to experiment. But, the first time you do it you'll know it. Since you have a UTEC, log each and every run. That way you can see what you need to work on.
I run 93 octane gas all the time. When I go to the track, I try to go with about 1/4 tank, then add 2 gallons of race gas (available at the track for $3.99/gallon - 108 octane) to my tank. So far no knocks recorded.