Congratulations on your SS1000! I tend to have trouble sleeping the night before any big ride. My mind is usually going full-speed thinking about the impending ride and repeatedly going over check-lists.
First and foremost, the IBA holds safety as the main concern for any rider. Excessive speed and/or reckless driving can get a certificate denied, or even revoked at a later time.
To accomplish a SS1000, the minimum required is to ride at least 1,000 miles in twenty-four hours. That breaks down to a minimum of 41.7 mph moving average for a 24 hour period. A rider could take rural roads with a 55mph speed limit and still have a 10+ minute stop every hour.
West of the Mississippi, the speed limits tend to be much higher. 65-70 mph is common, with a few states having 75mph (and I-10/I-20 in West TX at 80mph daytime).
With interstate speeds of 65-75mph, it is not difficult to do SS1000 in 17-19 hours, while never exceeding the posted speed limit. The key is time management whenever one makes a pit stop.
My 1,000 mile rides tend to take about 18 hours. I tend to stop every 200 miles or so, and minimize my time stopped. Why do I do it? I love to ride and see the US from the seat of my cycle(s).